* Update docs for ERC20 and ERC721

* Add EnumerableMap to docs

* Update misc guides

* Apply suggestions from code review

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* Implement AddressSet in terms of a generic Set

* Add Uint256Set

* Add EnumerableMap

* Fix wording on EnumerableSet docs and tests

* Refactor ERC721 using EnumerableSet and EnumerableMap

* Fix tests

* Fix linter error

* Gas optimization for EnumerableMap

* Gas optimization for EnumerableSet

* Remove often not-taken if from Enumerable data structures

* Fix failing test

* Gas optimization for EnumerableMap

* Fix linter errors

* Add comment for clarification

* Improve test naming

* Rename EnumerableMap.add to set

* Add overload for EnumerableMap.get with custom error message

* Improve Enumerable docs

* Rename Uint256Set to UintSet

* Add changelog entry

* Merge ERC20Detailed into ERC20, make derived contracts abstract

* Fix Create2 tests

* Fix failing test

* Default decimals to 18

* Add tests for setupDecimals

* Add changelog entry

* Update CHANGELOG.md

* Update CHANGELOG.md

* Replace isConstructor for !isContract

* Update CHANGELOG.md

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* Remove _grantRole and _revokeRole, replace with _setupRole

* Make all external AccessControl functions public

* Remove Ownable._transferOwnership

* Rename ERC721's _safeTransferFrom and _transferFrom to _safeTransfer and _transfer

* Make all ERC721 external functions public

* Make all miscelaneous external functions public instead

* Add changelog entry

* Move calldata arguments to memory

* Update contracts/access/AccessControl.sol

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

* Restrict setupRole to the constructor

* Replace isConstructor for !isContract

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Bumps [@openzeppelin/cli](https://github.com/OpenZeppelin/openzeppelin-sdk) from 2.7.2 to 2.8.0.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-sdk/releases)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-sdk/compare/v2.7.2...v2.8.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* fix mentions of drafts.adoc

* fix 721.adoc

* Add revert if the bytecode length is not greater than zero

* Add value parameter to create2 deploy function

Add tests for contract balance revert and depositing funds

* Change parameter name to amount for clarity

* Fix test for value sending

* Fix linter error

* Change revert reason

* Improve Create2.deploy documentation

* Slight test improvement

* Add changelog entry

Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>

* Add revert reason to EnumerableSet.get.

* Rename EnumerableSet values to keys

* Rename get to at

* Add changelog entry

* Rename keys to values

* Add leading underscore to struct members

* Add IERC721Metadata implementation into ERC721

* Add IERC721Enumerable into ERC721

* Update ERC721Pausable and ERC721Burnable

* Delete ERC721Metadata, ERC721Enumerable and ERC721 (now ERC721)

* Update mocks

* Update tests

* Update contracts/token/ERC721/ERC721.sol

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

* Make ERC721Pausable and ERC721Burnable abstract

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.4.0...6.4.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* Upgrade to latest solhint rc

* Add private-vars-leading-underscore linter rule

* Add leading underscore to GSNRecipient constants

* Remove leading underscore from ERC165Checker functions

* Add leading underscore to multiple private constants

* Fix linter errors in mocks

* Add leading underscore to ERC777's ERC1820 registry

* Add changelog entry

* Add signed to unsigned conversion to SafeCast

* Update SafeCast exception message

* Add test for SafeCast int to uint conversion

- Update SafeCastMock
- Add tests for SafeCast int256 to uint256

* Update SafeCast int to uint definition

Apply suggestions from code review.

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

* Update test for SafeCast int to uint conversion

* Update SafeCast test after code review

- Change "downcasts" to "casts"
- Move test closer to its function

* Fix error in SafeCast toUint256 description

* Fix breaking error in SafeCast

* Add uint256 to int256 conversion to SafeCast

- Add function
- Add mock
- Add test

* Update SafeCast unsigned to signed conversion

- Update error in conversion to be more clear
- Update constants in test to be powers of 2 instead of shifts

* Add changelog entry

* Update SafeCast tests

- Add minus in INT256_MIN for clarity

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

Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>

Bumps solidity-docgen from 0.4.0-beta.1 to 0.4.1.

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [mocha](https://github.com/mochajs/mocha) from 7.1.0 to 7.1.1.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v7.1.0...v7.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [eslint-config-standard](https://github.com/standard/eslint-config-standard) from 14.1.0 to 14.1.1.
- [Release notes](https://github.com/standard/eslint-config-standard/releases)
- [Changelog](https://github.com/standard/eslint-config-standard/blob/master/CHANGELOG.md)
- [Commits](https://github.com/standard/eslint-config-standard/compare/v14.1.0...v14.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* remove pass:normal from docs template

* add back pass:normal for auto links

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.1.2 to 4.7.3. **This update includes a security fix.**
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/wycats/handlebars.js/blob/master/release-notes.md)
- [Commits](https://github.com/wycats/handlebars.js/compare/v4.1.2...v4.7.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: Nicolás Venturo <nicolas.venturo@gmail.com>

Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.3 to 6.4.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/5.7.3...6.4.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* Make the sender the operator

* Make hook methods private

* Add changelog entry

Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.4.0...6.4.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

* Remove Address.toPayable

* Add changelog entry

* Make IERC721 contracts interfaces instead

* Bump minimum compiler version for IERC721

* Remove ERC721.burn(owner, tokenId)

* Remove ERC721._checkOnERC721Received from the contract's API

* Fix linter error

* Remove Escrow and PullPayment withdrawWithGas, replace for withdraw

* Add changelog entry

* Add reentrancy notice

* Remove Roles

* Add AccessControl and tests

* Removed IAccessControl

* Add RoleGranted and RoleRevoked events

* Make roles grantable and revokable regardless of their previous status

* Fix typo

* Add documentation

* Cleanup tests

* Add enumeration tests

* Add _setRoleAdmin tests

* Fix lint error

* Fix AccessControl link in docs

* WIP on access control guide

* Rename getRoleMembersCount

* Add tests for new role admin

* Make AccessControl GSN compatible

* Update access control guide

* Rename admin to adminRole

* Rename roleIds to roles

* Add 'operator' to RoleGranted and RoleRevoked events.

* Only emit events if the roles were not previously granted/revoked

* Uncomment expectEvent.not tests

* Rename operator to sender

* Add changelog entry

* Move Pausable into utils

* Move Strings into utils

* Move Counters into utils

* Move SignedSafeMath into math

* Remove ERC1046

* Make ERC20Snapshot.snapshot internal

* Move ERC20Snapshot into ERC20

* Add drafts deprecation notice

* Remove drafts directory

* Add changelog entry

* Apply suggestions from code review

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* Remove Ownable.isOwner.

* Remove ownable behavior from tests

* Make Escrow use Ownable instead of Secondary

* Migrate GSNRecipientERC20Fee to Ownable

* Remove Secondary

* Move Ownable to access directory

* Remove mentions of Secondary

* Add changelog entry

* Move Ownable tests to access

* Remove unused mock

* Remove ERC20._burnFrom

* Add changelog entry

Bumps [@openzeppelin/cli](https://github.com/OpenZeppelin/openzeppelin-sdk) from 2.7.1 to 2.7.2.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-sdk/releases)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-sdk/compare/v2.7.1...v2.7.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [@openzeppelin/test-helpers](https://github.com/OpenZeppelin/openzeppelin-test-helpers) from 0.5.4 to 0.5.5.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-test-helpers/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-test-helpers/blob/master/CHANGELOG.md)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-test-helpers/compare/v0.5.4...v0.5.5)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [@openzeppelin/gsn-provider](https://github.com/OpenZeppelin/openzeppelin-gsn-provider) from 0.1.9 to 0.1.10.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-gsn-provider/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-gsn-provider/blob/master/CHANGELOG.md)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-gsn-provider/compare/v0.1.9...v0.1.10)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.4.0...6.4.1)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* Remove crowdsales from sidebar documentation, add links to old version

* Remove mentions of Crowdsales from the documentation