Remove redundant @dev tags (#995)

* Remove redundant @dev tags

* Remove redundant @notice tags

contracts/ECRecovery.sol

@@ -3,12 +3,9 @@ pragma solidity ^0.4.24;
 
 /**
  * @title Eliptic curve signature operations
- *
  * @dev Based on https://gist.github.com/axic/5b33912c6f61ae6fd96d6c4a47afde6d
- *
  * TODO Remove this library once solidity supports passing a signature to ecrecover.
  * See https://github.com/ethereum/solidity/issues/864
- *
  */
 
 library ECRecovery {
@@ -59,7 +56,7 @@ library ECRecovery {
   /**
    * toEthSignedMessageHash
    * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
-   * @dev and hash the result
+   * and hash the result
    */
   function toEthSignedMessageHash(bytes32 hash)
     internal

contracts/LimitBalance.sol

@@ -4,8 +4,8 @@ pragma solidity ^0.4.24;
 /**
  * @title LimitBalance
  * @dev Simple contract to limit the balance of child contract.
- * @dev Note this doesn't prevent other contracts to send funds by using selfdestruct(address);
- * @dev See: https://github.com/ConsenSys/smart-contract-best-practices#remember-that-ether-can-be-forcibly-sent-to-an-account
+ * Note this doesn't prevent other contracts to send funds by using selfdestruct(address);
+ * See: https://github.com/ConsenSys/smart-contract-best-practices#remember-that-ether-can-be-forcibly-sent-to-an-account
  */
 contract LimitBalance {
 

contracts/MerkleProof.sol

@@ -3,8 +3,8 @@ pragma solidity ^0.4.24;
 
 /*
  * @title MerkleProof
- * @dev Merkle proof verification
- * @note Based on https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
+ * @dev Merkle proof verification based on
+ * https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
  */
 library MerkleProof {
   /*

contracts/access/SignatureBouncer.sol

@@ -9,28 +9,25 @@ import "../ECRecovery.sol";
  * @title SignatureBouncer
  * @author PhABC, Shrugs and aflesher
  * @dev Bouncer allows users to submit a signature as a permission to do an action.
- * @dev If the signature is from one of the authorized bouncer addresses, the signature
- * @dev is valid. The owner of the contract adds/removes bouncers.
- * @dev Bouncer addresses can be individual servers signing grants or different
- * @dev users within a decentralized club that have permission to invite other members.
- * @dev
- * @dev This technique is useful for whitelists and airdrops; instead of putting all
- * @dev valid addresses on-chain, simply sign a grant of the form
- * @dev keccak256(abi.encodePacked(`:contractAddress` + `:granteeAddress`)) using a valid bouncer address.
- * @dev Then restrict access to your crowdsale/whitelist/airdrop using the
- * @dev `onlyValidSignature` modifier (or implement your own using isValidSignature).
- * @dev
- * @dev In addition to `onlyValidSignature`, `onlyValidSignatureAndMethod` and
- * @dev `onlyValidSignatureAndData` can be used to restrict access to only a given method
- * @dev or a given method with given parameters respectively.
- * @dev
- * @dev See the tests Bouncer.test.js for specific usage examples.
+ * If the signature is from one of the authorized bouncer addresses, the signature
+ * is valid. The owner of the contract adds/removes bouncers.
+ * Bouncer addresses can be individual servers signing grants or different
+ * users within a decentralized club that have permission to invite other members.
+ * This technique is useful for whitelists and airdrops; instead of putting all
+ * valid addresses on-chain, simply sign a grant of the form
+ * keccak256(abi.encodePacked(`:contractAddress` + `:granteeAddress`)) using a valid bouncer address.
+ * Then restrict access to your crowdsale/whitelist/airdrop using the
+ * `onlyValidSignature` modifier (or implement your own using isValidSignature).
+ * In addition to `onlyValidSignature`, `onlyValidSignatureAndMethod` and
+ * `onlyValidSignatureAndData` can be used to restrict access to only a given method
+ * or a given method with given parameters respectively.
+ * See the tests Bouncer.test.js for specific usage examples.
  * @notice A method that uses the `onlyValidSignatureAndData` modifier must make the _sig
- * @notice parameter the "last" parameter. You cannot sign a message that has its own
- * @notice signature in it so the last 128 bytes of msg.data (which represents the
- * @notice length of the _sig data and the _sig data itself) is ignored when validating.
- * @notice Also non fixed sized parameters make constructing the data in the signature
- * @notice much more complex. See https://ethereum.stackexchange.com/a/50616 for more details.
+ * parameter the "last" parameter. You cannot sign a message that has its own
+ * signature in it so the last 128 bytes of msg.data (which represents the
+ * length of the _sig data and the _sig data itself) is ignored when validating.
+ * Also non fixed sized parameters make constructing the data in the signature
+ * much more complex. See https://ethereum.stackexchange.com/a/50616 for more details.
  */
 contract SignatureBouncer is Ownable, RBAC {
   using ECRecovery for bytes32;
@@ -146,7 +143,7 @@ contract SignatureBouncer is Ownable, RBAC {
 
   /**
    * @dev internal function to convert a hash to an eth signed message
-   * @dev and then recover the signature and check it against the bouncer role
+   * and then recover the signature and check it against the bouncer role
    * @return bool
    */
   function isValidDataHash(bytes32 hash, bytes _sig)

contracts/access/Whitelist.sol

@@ -8,7 +8,7 @@ import "../ownership/rbac/RBAC.sol";
 /**
  * @title Whitelist
  * @dev The Whitelist contract has a whitelist of addresses, and provides basic authorization control functions.
- * @dev This simplifies the implementation of "user permissions".
+ * This simplifies the implementation of "user permissions".
  */
 contract Whitelist is Ownable, RBAC {
   event WhitelistedAddressAdded(address addr);

contracts/examples/RBACWithAdmin.sol

@@ -7,14 +7,13 @@ import "../ownership/rbac/RBAC.sol";
  * @title RBACWithAdmin
  * @author Matt Condon (@Shrugs)
  * @dev It's recommended that you define constants in the contract,
- * @dev like ROLE_ADMIN below, to avoid typos.
- * @dev
- * @dev NOTE: RBACWithAdmin is probably too expansive and powerful for your
- * @dev  application; an admin is actually able to change any address to any role
- * @dev  which is a very large API surface. It's recommended that you follow a strategy
- * @dev  of strictly defining the abilities of your roles
- * @dev  and the API-surface of your contract.
- * @dev  This is just an example for example's sake.
+ * like ROLE_ADMIN below, to avoid typos.
+ * @notice RBACWithAdmin is probably too expansive and powerful for your
+ * application; an admin is actually able to change any address to any role
+ * which is a very large API surface. It's recommended that you follow a strategy
+ * of strictly defining the abilities of your roles
+ * and the API-surface of your contract.
+ * This is just an example for example's sake.
  */
 contract RBACWithAdmin is RBAC {
   /**

contracts/introspection/ERC165.sol

@@ -11,7 +11,7 @@ interface ERC165 {
    * @notice Query if a contract implements an interface
    * @param _interfaceId The interface identifier, as specified in ERC-165
    * @dev Interface identification is specified in ERC-165. This function
-   * @dev  uses less than 30,000 gas.
+   * uses less than 30,000 gas.
    */
   function supportsInterface(bytes4 _interfaceId)
     external

contracts/introspection/SupportsInterfaceWithLookup.sol

@@ -22,7 +22,7 @@ contract SupportsInterfaceWithLookup is ERC165 {
 
   /**
    * @dev A contract implementing SupportsInterfaceWithLookup
-   * @dev  implement ERC165 itself
+   * implement ERC165 itself
    */
   constructor()
     public

contracts/ownership/HasNoEther.sol

@@ -17,7 +17,7 @@ contract HasNoEther is Ownable {
 
   /**
   * @dev Constructor that rejects incoming Ether
-  * @dev The `payable` flag is added so we can access `msg.value` without compiler warning. If we
+  * The `payable` flag is added so we can access `msg.value` without compiler warning. If we
   * leave out payable, then Solidity will allow inheriting contracts to implement a payable
   * constructor. By doing it this way we prevent a payable constructor from working. Alternatively
   * we could use assembly to access msg.value.

contracts/ownership/Superuser.sol

@@ -8,8 +8,8 @@ import "./rbac/RBAC.sol";
 /**
  * @title Superuser
  * @dev The Superuser contract defines a single superuser who can transfer the ownership 
- * @dev of a contract to a new address, even if he is not the owner.
- * @dev A superuser can transfer his role to a new address.
+ * of a contract to a new address, even if he is not the owner. 
+ * A superuser can transfer his role to a new address. 
  */
 contract Superuser is Ownable, RBAC {
   string public constant ROLE_SUPERUSER = "superuser";

contracts/ownership/rbac/RBAC.sol

@@ -7,8 +7,8 @@ import "./Roles.sol";
  * @title RBAC (Role-Based Access Control)
  * @author Matt Condon (@Shrugs)
  * @dev Stores and provides setters and getters for roles and addresses.
- * @dev Supports unlimited numbers of roles and addresses.
- * @dev See //contracts/mocks/RBACMock.sol for an example of usage.
+ * Supports unlimited numbers of roles and addresses.
+ * See //contracts/mocks/RBACMock.sol for an example of usage.
  * This RBAC method uses strings to key roles. It may be beneficial
  * for you to write your own implementation of this interface using Enums or similar.
  * It's also recommended that you define constants in the contract, like ROLE_ADMIN below,

contracts/token/ERC20/ERC20Basic.sol

@@ -4,7 +4,7 @@ pragma solidity ^0.4.24;
 /**
  * @title ERC20Basic
  * @dev Simpler version of ERC20 interface
- * @dev see https://github.com/ethereum/EIPs/issues/179
+ * See https://github.com/ethereum/EIPs/issues/179
  */
 contract ERC20Basic {
   function totalSupply() public view returns (uint256);

contracts/token/ERC20/MintableToken.sol

@@ -7,7 +7,6 @@ import "../../ownership/Ownable.sol";
 /**
  * @title Mintable token
  * @dev Simple ERC20 Token example, with mintable token creation
- * @dev Issue: * https://github.com/OpenZeppelin/openzeppelin-solidity/issues/120
  * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
  */
 contract MintableToken is StandardToken, Ownable {

contracts/token/ERC20/StandardToken.sol

@@ -8,8 +8,8 @@ import "./ERC20.sol";
  * @title Standard ERC20 token
  *
  * @dev Implementation of the basic standard token.
- * @dev https://github.com/ethereum/EIPs/issues/20
- * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
+ * https://github.com/ethereum/EIPs/issues/20
+ * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
  */
 contract StandardToken is ERC20, BasicToken {
 
@@ -43,7 +43,6 @@ contract StandardToken is ERC20, BasicToken {
 
   /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
-   *
    * Beware that changing an allowance with this method brings the risk that someone may use both the old
    * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
    * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
@@ -76,7 +75,6 @@ contract StandardToken is ERC20, BasicToken {
 
   /**
    * @dev Increase the amount of tokens that an owner allowed to a spender.
-   *
    * approve should be called when allowed[_spender] == 0. To increment
    * allowed value is better to use this function to avoid 2 calls (and wait until
    * the first transaction is mined)
@@ -99,7 +97,6 @@ contract StandardToken is ERC20, BasicToken {
 
   /**
    * @dev Decrease the amount of tokens that an owner allowed to a spender.
-   *
    * approve should be called when allowed[_spender] == 0. To decrement
    * allowed value is better to use this function to avoid 2 calls (and wait until
    * the first transaction is mined)

contracts/token/ERC721/DeprecatedERC721.sol

@@ -6,7 +6,7 @@ import "./ERC721.sol";
 /**
  * @title ERC-721 methods shipped in OpenZeppelin v1.7.0, removed in the latest version of the standard
  * @dev Only use this interface for compatibility with previously deployed contracts
- * @dev Use ERC721 for interacting with new contracts which are standard-compliant
+ * Use ERC721 for interacting with new contracts which are standard-compliant
  */
 contract DeprecatedERC721 is ERC721 {
   function takeOwnership(uint256 _tokenId) public;

contracts/token/ERC721/ERC721BasicToken.sol

@@ -111,9 +111,9 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Approves another address to transfer the given token ID
-   * @dev The zero address indicates there is no approved address.
-   * @dev There can only be one approved address per token at a given time.
-   * @dev Can only be called by the token owner or an approved operator.
+   * The zero address indicates there is no approved address.
+   * There can only be one approved address per token at a given time.
+   * Can only be called by the token owner or an approved operator.
    * @param _to address to be approved for the given token ID
    * @param _tokenId uint256 ID of the token to be approved
    */
@@ -137,7 +137,7 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Sets or unsets the approval of a given operator
-   * @dev An operator is allowed to transfer all tokens of the sender on their behalf
+   * An operator is allowed to transfer all tokens of the sender on their behalf
    * @param _to operator address to set the approval
    * @param _approved representing the status of the approval to be set
    */
@@ -166,8 +166,8 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Transfers the ownership of a given token ID to another address
-   * @dev Usage of this method is discouraged, use `safeTransferFrom` whenever possible
-   * @dev Requires the msg sender to be the owner, approved, or operator
+   * Usage of this method is discouraged, use `safeTransferFrom` whenever possible
+   * Requires the msg sender to be the owner, approved, or operator
    * @param _from current owner of the token
    * @param _to address to receive the ownership of the given token ID
    * @param _tokenId uint256 ID of the token to be transferred
@@ -192,11 +192,12 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Safely transfers the ownership of a given token ID to another address
-   * @dev If the target address is a contract, it must implement `onERC721Received`,
+   * If the target address is a contract, it must implement `onERC721Received`,
    * which is called upon a safe transfer, and return the magic value
    * `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`; otherwise,
    * the transfer is reverted.
-   * @dev Requires the msg sender to be the owner, approved, or operator
+   *
+   * Requires the msg sender to be the owner, approved, or operator
    * @param _from current owner of the token
    * @param _to address to receive the ownership of the given token ID
    * @param _tokenId uint256 ID of the token to be transferred
@@ -215,11 +216,11 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Safely transfers the ownership of a given token ID to another address
-   * @dev If the target address is a contract, it must implement `onERC721Received`,
+   * If the target address is a contract, it must implement `onERC721Received`,
    * which is called upon a safe transfer, and return the magic value
    * `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`; otherwise,
    * the transfer is reverted.
-   * @dev Requires the msg sender to be the owner, approved, or operator
+   * Requires the msg sender to be the owner, approved, or operator
    * @param _from current owner of the token
    * @param _to address to receive the ownership of the given token ID
    * @param _tokenId uint256 ID of the token to be transferred
@@ -267,7 +268,7 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Internal function to mint a new token
-   * @dev Reverts if the given token ID already exists
+   * Reverts if the given token ID already exists
    * @param _to The address that will own the minted token
    * @param _tokenId uint256 ID of the token to be minted by the msg.sender
    */
@@ -279,7 +280,7 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Internal function to burn a specific token
-   * @dev Reverts if the token does not exist
+   * Reverts if the token does not exist
    * @param _tokenId uint256 ID of the token being burned by the msg.sender
    */
   function _burn(address _owner, uint256 _tokenId) internal {
@@ -290,7 +291,7 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Internal function to clear current approval of a given token ID
-   * @dev Reverts if the given address is not indeed the owner of the token
+   * Reverts if the given address is not indeed the owner of the token
    * @param _owner owner of the token
    * @param _tokenId uint256 ID of the token to be transferred
    */
@@ -326,7 +327,7 @@ contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
 
   /**
    * @dev Internal function to invoke `onERC721Received` on a target address
-   * @dev The call is not executed if the target address is not a contract
+   * The call is not executed if the target address is not a contract
    * @param _from address representing the previous owner of the given token ID
    * @param _to target address that will receive the tokens
    * @param _tokenId uint256 ID of the token to be transferred

contracts/token/ERC721/ERC721Token.sol

@@ -80,7 +80,7 @@ contract ERC721Token is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
 
   /**
    * @dev Returns an URI for a given token ID
-   * @dev Throws if the token ID does not exist. May return an empty string.
+   * Throws if the token ID does not exist. May return an empty string.
    * @param _tokenId uint256 ID of the token to query
    */
   function tokenURI(uint256 _tokenId) public view returns (string) {
@@ -116,7 +116,7 @@ contract ERC721Token is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
 
   /**
    * @dev Gets the token ID at a given index of all the tokens in this contract
-   * @dev Reverts if the index is greater or equal to the total number of tokens
+   * Reverts if the index is greater or equal to the total number of tokens
    * @param _index uint256 representing the index to be accessed of the tokens list
    * @return uint256 token ID at the given index of the tokens list
    */
@@ -127,7 +127,7 @@ contract ERC721Token is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
 
   /**
    * @dev Internal function to set the token URI for a given token
-   * @dev Reverts if the token ID does not exist
+   * Reverts if the token ID does not exist
    * @param _tokenId uint256 ID of the token to set its URI
    * @param _uri string URI to assign
    */
@@ -173,7 +173,7 @@ contract ERC721Token is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
 
   /**
    * @dev Internal function to mint a new token
-   * @dev Reverts if the given token ID already exists
+   * Reverts if the given token ID already exists
    * @param _to address the beneficiary that will own the minted token
    * @param _tokenId uint256 ID of the token to be minted by the msg.sender
    */
@@ -186,7 +186,7 @@ contract ERC721Token is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
 
   /**
    * @dev Internal function to burn a specific token
-   * @dev Reverts if the token does not exist
+   * Reverts if the token does not exist
    * @param _owner owner of the token to burn
    * @param _tokenId uint256 ID of the token being burned by the msg.sender
    */

contracts/token/ERC827/ERC827.sol

@@ -8,8 +8,8 @@ import "../ERC20/ERC20.sol";
  * @title ERC827 interface, an extension of ERC20 token standard
  *
  * @dev Interface of a ERC827 token, following the ERC20 standard with extra
- * @dev methods to transfer value and data and execute calls in transfers and
- * @dev approvals.
+ * methods to transfer value and data and execute calls in transfers and
+ * approvals.
  */
 contract ERC827 is ERC20 {
   function approveAndCall(

contracts/token/ERC827/ERC827Token.sol

@@ -10,28 +10,23 @@ import "../ERC20/StandardToken.sol";
  * @title ERC827, an extension of ERC20 token standard
  *
  * @dev Implementation the ERC827, following the ERC20 standard with extra
- * @dev methods to transfer value and data and execute calls in transfers and
- * @dev approvals.
- *
- * @dev Uses OpenZeppelin StandardToken.
+ * methods to transfer value and data and execute calls in transfers and
+ * approvals. Uses OpenZeppelin StandardToken.
  */
 contract ERC827Token is ERC827, StandardToken {
 
   /**
    * @dev Addition to ERC20 token methods. It allows to
-   * @dev approve the transfer of value and execute a call with the sent data.
-   *
-   * @dev Beware that changing an allowance with this method brings the risk that
-   * @dev someone may use both the old and the new allowance by unfortunate
-   * @dev transaction ordering. One possible solution to mitigate this race condition
-   * @dev is to first reduce the spender's allowance to 0 and set the desired value
-   * @dev afterwards:
-   * @dev https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
-   *
+   * approve the transfer of value and execute a call with the sent data.
+   * Beware that changing an allowance with this method brings the risk that
+   * someone may use both the old and the new allowance by unfortunate
+   * transaction ordering. One possible solution to mitigate this race condition
+   * is to first reduce the spender's allowance to 0 and set the desired value
+   * afterwards:
+   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    * @param _spender The address that will spend the funds.
    * @param _value The amount of tokens to be spent.
    * @param _data ABI-encoded contract call to call `_to` address.
-   *
    * @return true if the call function was executed successfully
    */
   function approveAndCall(
@@ -55,12 +50,10 @@ contract ERC827Token is ERC827, StandardToken {
 
   /**
    * @dev Addition to ERC20 token methods. Transfer tokens to a specified
-   * @dev address and execute a call with the sent data on the same transaction
-   *
+   * address and execute a call with the sent data on the same transaction
    * @param _to address The address which you want to transfer to
    * @param _value uint256 the amout of tokens to be transfered
    * @param _data ABI-encoded contract call to call `_to` address.
-   *
    * @return true if the call function was executed successfully
    */
   function transferAndCall(
@@ -83,13 +76,11 @@ contract ERC827Token is ERC827, StandardToken {
 
   /**
    * @dev Addition to ERC20 token methods. Transfer tokens from one address to
-   * @dev another and make a contract call on the same transaction
-   *
+   * another and make a contract call on the same transaction
    * @param _from The address which you want to send tokens from
    * @param _to The address which you want to transfer to
    * @param _value The amout of tokens to be transferred
    * @param _data ABI-encoded contract call to call `_to` address.
-   *
    * @return true if the call function was executed successfully
    */
   function transferFromAndCall(
@@ -111,13 +102,11 @@ contract ERC827Token is ERC827, StandardToken {
 
   /**
    * @dev Addition to StandardToken methods. Increase the amount of tokens that
-   * @dev an owner allowed to a spender and execute a call with the sent data.
-   *
-   * @dev approve should be called when allowed[_spender] == 0. To increment
-   * @dev allowed value is better to use this function to avoid 2 calls (and wait until
-   * @dev the first transaction is mined)
-   * @dev From MonolithDAO Token.sol
-   *
+   * an owner allowed to a spender and execute a call with the sent data.
+   * approve should be called when allowed[_spender] == 0. To increment
+   * allowed value is better to use this function to avoid 2 calls (and wait until
+   * the first transaction is mined)
+   * From MonolithDAO Token.sol
    * @param _spender The address which will spend the funds.
    * @param _addedValue The amount of tokens to increase the allowance by.
    * @param _data ABI-encoded contract call to call `_spender` address.
@@ -143,13 +132,11 @@ contract ERC827Token is ERC827, StandardToken {
 
   /**
    * @dev Addition to StandardToken methods. Decrease the amount of tokens that
-   * @dev an owner allowed to a spender and execute a call with the sent data.
-   *
-   * @dev approve should be called when allowed[_spender] == 0. To decrement
-   * @dev allowed value is better to use this function to avoid 2 calls (and wait until
-   * @dev the first transaction is mined)
-   * @dev From MonolithDAO Token.sol
-   *
+   * an owner allowed to a spender and execute a call with the sent data.
+   * approve should be called when allowed[_spender] == 0. To decrement
+   * allowed value is better to use this function to avoid 2 calls (and wait until
+   * the first transaction is mined)
+   * From MonolithDAO Token.sol
    * @param _spender The address which will spend the funds.
    * @param _subtractedValue The amount of tokens to decrease the allowance by.
    * @param _data ABI-encoded contract call to call `_spender` address.