* Merge GSNContext into GSNRecipient

* Update GSNRecipient.test.js

* Update GSNRecipient.sol

* Make GSNRecipient inherit from Context

* Improve IRelayRecipient docs

* Fix link

* Update IRelayHub docs to the docsite format

* Update IRelayRecipient docs to the dociste format

* Fix typo

* Improve GSN readme

* Fix link

* Update GSNRecipient docs

* Apply suggestions from code review

Co-Authored-By: Andrew B Coathup <28278242+abcoathup@users.noreply.github.com>

* Apply suggestions from code review

Co-Authored-By: Andrew B Coathup <28278242+abcoathup@users.noreply.github.com>

* Apply suggestions from code review

Co-Authored-By: Andrew B Coathup <28278242+abcoathup@users.noreply.github.com>

* Replace confirmRelayedCall with approveRelayedCall

* Update gsn-bouncers.adoc

* Update deprecated enums

Bumps [mixin-deep](https://github.com/jonschlinkert/mixin-deep) from 1.3.1 to 1.3.2.
- [Release notes](https://github.com/jonschlinkert/mixin-deep/releases)
- [Commits](https://github.com/jonschlinkert/mixin-deep/compare/1.3.1...1.3.2)

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

* added tests for getApproved

* added tests for getApproved

* added to changelog

* Corrected some linting issues

* Removed unneccrary tests as pointed out here: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1820/commits/b49c2de086621745955be83a34a06de65e95c76c#r307927816

* Correct Changelog character

* Update ERC721.behavior.js

Bumps [eslint-utils](https://github.com/mysticatea/eslint-utils) from 1.3.1 to 1.4.2.
- [Release notes](https://github.com/mysticatea/eslint-utils/releases)
- [Commits](https://github.com/mysticatea/eslint-utils/compare/v1.3.1...v1.4.2)

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

* Adding in "<<: *defaults" under "coverage"

* Refactoring by capturing similar setup commands into single alias

* Reverting changes, I am not certain exactly how to refactor these setup steps, but at least the &default refactor can be made.

Fix typos in instructions

* Remove SignatureBouncer

* Update changelog entry

* Fix coverage

* Update CHANGELOG.md

* move gsn link

* change underscore to dash

* add content to gsn api ref

* change link of GSN announcement

* Update contracts/GSN/bouncers/GSNBouncerERC20Fee.sol

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

* fix crossreference to gsn guide

* Remove intro from gsn guide

We are moving the intro to the top-level in the docsite, and focusing this guide into writing gsn-enabled contracts.

* Update docs/modules/ROOT/pages/gsn.adoc

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

* Update gsn.adoc

* Update gsn_advanced.adoc

Line 15 - where it says, "prevent malicious users from spending the transactions subsidy", with transactions subsidy, is it supposed to be possessive "transaction's subsidy" or is the plural in the wrong place "transaction subsidies"?

Line 176 - where it says "or it is not allowed to spend that amount". Is IT referring to the sender/person or the tx? If IT refers to a person, then change to "or they are not allowed..." for gender neutral.

Line 213 - Where it says, "Please not how the gas cost estimation", a verb is missing, please what?

* Update gsn_advanced.adoc

Apply suggestions by Amy

* switch to using Context internally

* add context import

* Add smoke test to make sure enabling GSN support works

* Update test/GSN/ERC721GSNRecipientMock.test.js

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

* Upgrade truffle

* add missing awaits

* Revert "Upgrade truffle"

This reverts commit f9b0ba9019650fdbf8919a33e6fba834689e6b04.

> openzeppelin-solidity@2.3.0 lint /home/luiserebii/github/openzeppelin-solidity
> npm run lint:js && npm run lint:sol

> openzeppelin-solidity@2.3.0 lint:js /home/luiserebii/github/openzeppelin-solidity
> eslint .

> openzeppelin-solidity@2.3.0 lint:sol /home/luiserebii/github/openzeppelin-solidity
> solhint --max-warnings 0 "contracts/**/*.sol", alongside some minor grammatical corrections