Uses the explicit address(0) for the zero address

* Make contracts 4.24 compatible

* fix: defer lookup-specific info to implementations

* fix: change inheritance order, fix import

* ownable: add a notice on renounceOwnership

* Apply the suggestion by @shrugs

* addressed unchecked return value in AllowanceCrowdsale #945 using SafeERC20

* make _tokenId indexed in Transfer and Approval events

via: https://github.com/ethereum/EIPs/pull/1124/files

* fix: make name() and symbol() external instead of public

* feat: implement ERC721's ERC165

* feat: erc165 tests

* fix: don't use chai-as-promised in direct await

* fix: reorganize to /introspection

* feat: abstract all erc165 tests to a behavior

* feat: disallow registering 0xffffffff

* Refactoring Superuser contract to allow Owners to transfer ownership when they are not superusers #50

* Refactoring tests to create a contract instance for each of them #50

* add a comment on detailed erc20 token #953

*  update sha3 1.2.0 -> 1.2.2 for node 10 compatibility

* update nan 2.6.2 -> 2.10.0 for node 10 compatibility

* commit new package-lock.json format generated by npm 6

* fix: add comment about rbacwithadmin being rather powerful
* fix: move RBACWithAdmin to examples

* Update README.md

* update embark import to use the v1.9.0 tag instead of master

* Update README.md

* Adding new Superuser contract + tests

* added the RBACMintableToken
* added MintedCrowdsale with RBACMintableToken test
* added a mintable behaviour for tests
* moved minting tests in behaviour
* created a minted crowdsale behaviour to be tested with both mintable and rbacmintable token

* update solidity-coverage to ^0.5.0

* update truffle dependency to ^4.1.8

* update solium to ^1.1.7

* update all contracts to solidity ^0.4.23

* added function to renounce ownership

* Provide an Ownable behavior for testing (#905)

* Fix indentation

* Convert to use should assertions

* feat: refactor whitelist.sol to use RBAC

* fix: remove poor backwards compat attempt

* Removed asserts and replaced them in favor of require

* Adapted tests to work with requires

* ignore everything but official contracts for npm

* add tests to npm package

* remove truffle migrations stuff

* remove seemingly unused npm dependency

* clean up dependencies