* 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