* Improved bounty tests.

* Fixed linter errors.

* Addressed review comments.

(cherry picked from commit ae109f69)

* Removed mintingFinished from ERC20Mintable.

* Removed MintingFinished from ERC721Mintable.

* Removed MintingFinished event.

(cherry picked from commit 5fdeaa81)

(cherry picked from commit db2e1d2c)

* Add the missing test for ERC721Holder

* fix lint

* Move the holder test to a separate file

(cherry picked from commit 396680b8)

* release candidate v2.0.0-rc.1

* fix linter error

(cherry picked from commit c12a1c68)

* Roles now emit events in construction and when renouncing.

(cherry picked from commit 21198bf1)