* Changed Crowdsale inheritance order.

* Changed FinalizableCrowdsale inheritance order.

(cherry picked from commit 3d86c58d)

* fixed visibility warnings

* solved visibility and line length warning

* change a test assertion that fails due to chai dependence update

* linter, constructor style and solved visibility warnings

* Changed Windows line endings to Unix.

* Use address(this) instead of this

It's preferred to use `address(this)` vs `this`

* Change to address(this) vs this

* optimizing ReentrancyGuard gas usage

* style fixed

Silences warning

* Making visibility explicit for storage variables

* Made BasicToken's variables internal.

* Add EditorConfig file.

This allows users with a wide variety of editors to easily code in
OpenZeppelin's preferred 2 space indentation code style.

See https://editorconfig.org for more information.

* Eslint: Always disallow trailing space

* Eslint: Error on missing EOL at file end

* Added an Architecture section that speaks to the different types of contracts
* Added a Tests section that provides high-level visibility into what is used for unit testing
* Added a How To Use and Modify OpenZeppelin Contracts section
* Added development principles to the existing Security section

* fix: solium linting errors, fixes #1092

* fix: remove uppercase requirement

We now ensure that if an exception is thrown while awaiting the promise,
the exception _has_ to be a revert. We throw 'Expected revert not
received' only afterwards. This solves any problems with confusing the
word 'revert'.

Fix #775

* Removed all instances of var.

* Sorted eslintrc rules.

* Made eslint rule severity explicit.

* Now prefering const over let.

* fix: bounty tests, superceeds #799

* fix: updates from PR notes

* Test: Remove chai-as-promised calls

* Test/Helpers: expectThrow accepts optional message

* NPM: Remove chai-as-promised

* Contracts/DestructibleMock: Fix lint

* Destructible no longer has a payable constructor.

* Fixed linter errors.

* Improved documentation for _preValidatePurchase in Crowdsale

* Added newline at EOF

* removed and tested unecessary gas cost

* linted

* Revert package-lock.json update.

This reverts commit 054598ce7f125b0e1aa4c463f047ac77771cf635.

* Added clarifying comments.

* decrease approval condition fix (greater than and equal to)

* sol lint fixed

* Improved standard token decreaseApprovalTests.

* Update StandardToken.sol

* Slight improvement in gas efficiency

Users tend to attempt to over-spend more than they attempt to burn non-burnable tokens. If the contract checks for overspending before assuring tokens are not being burnt a slight amount of gas might be saved in the long term.

* Changed before for beforeAll, refactored Bouncer tests.

* Fixed linter errors.

* fix: updates for SignatureBouncer tests and voucher construction

* feat: add AutoIncrementing contract

* feat: allow multiple counters per instance

* fix: some linting errors

* feat: use recommended implementaiton

* fix: remove .only in tests

* fix: PR notes

* fix: add note about incrementing counter

* Test helpers no longer rely on Babel.

* Behaviours are no longer imported.

* Removed Babel dependency.

* Fixed linter errors.

* Assume that token is mintable.

* ECRecover test should revert because of wrong calldata size

* fix: use expectThrow

* fix: ignore failing test until solc^0.5.0