* Added PausableCrowdsale contract
* Changed inheritance order to prevent "Linearization of inheritance graph impossible" error
* Updated mock PausableCrowdsaleImpl to new constructor syntax
* Broke function definition to multiple lines
Comply with new max line length
* Rename events to past-tense in PausableCrowdsale test
* Removed should.be.fullfilled from PausableCrowdsale tests
* Change import assertRevert to require in PausableCrowdsale tests
* Remove dependency on chai-as-promised and added BigNumber support in PausableCrowdsale tests
* reindent solidity with 4 spaces
* add missing view modifier in _preValidatePurchase
* convert assertRevert to new shoulFail helper
* add new setup helper
* use expectEvent
* convert to assert to chai should style
* add description to beforeEach blocks
* extract common step to beforeEach
* improve documentation
* revert inheritance error
* move PausableCrowdsale into crowdsale/validation
* make documentation more specific
* put whitespace in line with convention
* improve test suite account names
* undo beforeEach descriptions
* simplify tests
* fix transaction senders to be the anyone account
* make transaction senders more explicit
* remove mocha only
