Move SafeMath and create Math library for assorted operations

Add Crowdsale contracts

Added new test for a day passed scenario to the DayLimit contract

Add a TokenTimelock contract

fix(token): typo in documentation

it is superseded by the new crowdsale contracts

includes fix to MultisigWallet test because bigger balances result in
floating point errors (see #204)

Implemantation -> Implementation

change inheritance order for StandardToken and PausableToken

Remove all checks for short address attack

Fix typo in StandardToken allowance documentation

Removes install script

change uint to uint256

assert is now built in