* Basic idea
* Fine tuning idea
* Add comments / tidy up Crowdsale base class
* fixed TimedCrowdsale constructor
* added simple crowdsale test
* added HODL directory under home to store unused contracts. ugly hack to solve Crowdsale selection in tests, better way?
* Capped no longer inherits from Timed, added capReached() method (replacing hasEnded())
* added SafeMath in TimedCrowdsale for safety, CHECK whether it is inherited from Crowdsale
* several fixes related to separating Capped from Timed. functions renamed, mocks changed. Capped tests passing
* added TimedCrowdsaleImpl.sol, TimedCrowdsale tests, passed
* added Whitelisted implementation and test, passed.
* removed unnecessary super constructor call in WhitelistedCrowdsale, removed unused dependencies in tests
* renamed UserCappedCrowdsale to IndividuallyCappedCrowdsale, implemented IndividuallyCappedCrowdsaleImpl.sol and corresponding tests, passed.
* homogeneized use of using SafeMath for uint256 across validation crowdsales. checked that it IS indeed inherited, but leaving it there as per Frans suggestion.
* adding questions.md where I track questions, bugs and progress
* modified VariablePriceCrowdsale, added Impl.
* finished VariablePrice, fixed sign, added test, passing.
* changed VariablePrice to IncreasingPrice, added corresponding require()
* MintedCrowdsale done, mock implemented, test passing
* PremintedCrowdsale done, mocks, tests passing
* checked FinalizableCrowdsale
* PostDeliveryCrowdsale done, mock, tests passing.
* RefundableCrowdsale done. Detached Vault. modified mock and test, passing
* renamed crowdsale-refactor to crowdsale in contracts and test
* deleted HODL old contracts
* polished variable names in tests
* fixed typos and removed comments in tests
* Renamed 'crowdsale-refactor' to 'crowdsale' in all imports
* Fix minor param naming issues in Crowdsale functions and added documentation to Crowdsale.sol
* Added documentation to Crowdsale extensions
* removed residual comments and progress tracking files
* added docs for validation crowdsales
* Made user promises in PostDeliveryCrowdsale public so that users can query their promised token balance.
* added docs for distribution crowdsales
* renamed PremintedCrowdsale to AllowanceCrowdsale
* added allowance check function and corresponding test. fixed filename in AllowanceCrowdsale mock.
* spilt Crowdsale _postValidatePurchase in _postValidatePurchase and _updatePurchasingState. changed IndividuallyCappedCrowdsale accordingly.
* polished tests for linter, salve Travis
* polished IncreasingPriceCrowdsale.sol for linter.
* renamed and polished for linter WhitelistedCrowdsale test.
* fixed indentation in IncreasingPriceCrowdsaleImpl.sol for linter
* fixed ignoring token.mint return value in MintedCrowdsale.sol
* expanded docs throughout, fixed minor issues
* extended test coverage for IndividuallyCappedCrowdsale
* Extended WhitelistedCrwodsale test coverage
* roll back decoupling of RefundVault in RefundableCrowdsale
* moved cap exceedance checks in Capped and IndividuallyCapped crowdsales to _preValidatePurchase to save gas
* revert name change, IndividuallyCapped to UserCapped
* extended docs.
* added crowd whitelisting with tests
* added group capping, plus tests
* added modifiers in TimedCrowdsale and WhitelistedCrowdsale
* polished tests for linter
* moved check of whitelisted to modifier, mainly for testing coverage
* fixed minor ordering/polishingafter review
* modified TimedCrowdsale modifier/constructor ordering
* unchanged truffle-config.js
* changed indentation of visibility modifier in mocks
* changed naming of modifier and function to use Open/Closed for TimedCrowdsale
* changed ordering of constructor calls in SampleCrowdsale
* changed startTime and endTime to openingTime and closingTime throughout
* fixed exceeding line lenght for linter
* renamed _emitTokens to _deliverTokens
* renamed addCrowdToWhitelist to addManyToWhitelist
* renamed UserCappedCrowdsale to IndividuallyCappedCrowdsale
add missing public identifier in approveData in SmartToken contract
remove constact from showMessage function in message helper contract
move Message helper contract to mocks folder
move SmartTokenMock contract to mocks folder
