* Bump required compiler version to 0.5.2.

* Fix shadowed variable warning in ERC20Migrator.

* Rename Counter to Counters.

* Add dummy state variable to SafeERC20Helper.

* Update changelog entry.

* Fix CountersImpl name.

* Improve changelog entry.

* Now compiling using truffle 5.

* Migrated some test files, missing BN scientific notation usage.

* Now using BN time values.

* Migrate ERC20 tests.

* Migrate all ERC20 tests.

* Migrate utils, payment and ownership tests.

* All tests save ERC721 migrated.

* Migrated ERC721 tests.

* Fix lint errors.

* Delete old test helpers.

* Fix remaining crowdsale tests.

* Fix signature bouncer tests.

* Update how constants is used.

* Compile script pre-removes the build dir.

* Fix SafeMath tests.

* Revert "Compile script pre-removes the build dir."

This reverts commit 247e7451135d33c056a126e9e5fd77a24348018d.

* Fix linter errors.

* Upgrade openzeppelin-test-helpers dependency.

* Update openzeppelin-test-helpers dependency.

* Define math constants globally.

* Remove unnecessary ether unit.

* Roll back reduced ether amounts in tests.

* Remove unnecessary toNumber conversions.

* Delete compile script.

* Fixed failing test.

* Adding solhint, working on style fixes.

* Upgraded to solhint 1.5.0.

* Removed all references to Solium

* Updated mocks to make the pass the new linter rules.

* Reformatted the .solhint.json file a bit.

* Removed Solium configuration files.

* Remove Solium dependency.

* Add comment explaing disabled time rule in TokenVesting.

* Revert to the old (ugly?) style.

* Revert SignatureBouncerMock style.

* Fix ERC165InterfacesSupported interface.

* Rename WhitelisterRole to WhitelistAdminRole.

* Update WhitelistAdmin changelog entry.

* separate unsigned and signed safemath libraries

* update changelog entry for SignedSafeMath

* signing prefix added

* Minor improvement

* Successfully tested

* Minor improvements

* Minor improvements

* Revert "Dangling commas are now required. (#1359)"

This reverts commit a6889776.

* updates

* fixes #1404

* approve failing test

* suggested changes done

* ISafeERC20 removed

* conflict fixes

* added examples

* fixes #706

* linting

* fixes #204

* file fixing

* deep bignumber comparison removed

* Update SafeERC20Helper.sol

* Update IERC20.sol

* Update SafeERC20.sol

* Update package-lock.json

* Revert "deep bignumber comparison removed"

This reverts commit 230b27214fc96ab4c990b169bbc15df129bad657.

(cherry picked from commit 73cbad2f)

(cherry picked from commit 50367416)

(cherry picked from commit 7361ffd2)

* Now compiling in a separate directory using truffle 5.

* Ported to 0.5.1, now compiling using 0.5.1.

* test now also compiles using the truffle 5 hack.

* Downgraded to 0.5.0.

* Sorted scripts.

* Cleaned up the compile script a bit.

* Made the Crowdsale's constructor public again.

* Added changelog entry.

* Made all but Finalizable public.

* signed safe math

* fix lint errors

* refactor overflow checks and add descriptions

* remove incorrect description

* add test for reversed arguments in multiplication test

* fix power operator

* improve multiplication test descriptions

* Update SafeMath.test.js

* add feature to changelog

* Added changelog.

* Added PR template note.

* Update .github/PULL_REQUEST_TEMPLATE.md

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Update PULL_REQUEST_TEMPLATE.md

* Update CHANGELOG.md

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Update CHANGELOG.md

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Apply suggestions from code review

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Added more headers and sub-headers.

* Added deprecations category.

* Added PR links.

* Added PausableCrowdsale.

* Addressed review comments.

* Update CHANGELOG.md

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* 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

* Now only swapping when needed.

* Removed _addTokenTo and _removeTokenFrom

* Removed removeTokenFrom test.

* Added tests for ERC721 _mint and _burn

* _burn now uses the same swap and pop mechanism as _removeFromOwner

* Gas optimization on burn

* remove note that was fixed in #1526

* add build script

* add prepack script

* remove custom compilation steps

* Added WhitelisterRole.

* Added WhitelisteeRole and WhitelistedCrowdsale.

* Added WhitelistedCrowdsale tests.

* Whitelisters can now remove Whitelistees.

* PublicRole.behavior now supports a manager account, added Whitelistee tests.

* Rephrased tests, added test for whitelistees doing invalid purchases.

* Fixed linter error.

* Fixed typos

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Working around JS quirks

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Update PublicRole.behavior.js

* Renamed WhitelisteeRole to WhitelistedRole.

* Renamed WhitelistedCrowdsale to WhitelistCrowdsale.

* Now using the new test helper.

* Added basic documentation.

* Deprecated ERC721._burn(address, uint256)

* Added missing natspec comment.

* Fixed unnecessary dependency of RefundableCrowdsaleImpl on ERC20Mintable.

* Added PostDeliveryRefundableCrowdsale.

* Renamed to RefundablePostDeliveryCrowdsale.

* Added deprecation warning.

* Added _transferToken.

* _transferFrom is now usable by derived contracts, abstracted away enumerable behavior.

* Removed unnecesary check from _clearApprovals