Merge pull request googleapis#304 from dhermes/release-1.5.1

Release 1.5.1.

Merge pull request googleapis#292 from dhermes/release-1.5.0

Releasing 1.5.0.

Merge pull request googleapis#216 from craigcitro/new_release

Update for v1.4.12 release.

Merge pull request googleapis#187 from craigcitro/new_release

Update for v1.4.11 release.

Merge pull request googleapis#183 from craigcitro/new_release

Update for v1.4.10 release.

Merge pull request googleapis#180 from craigcitro/new_release

Update for v1.4.9 release.

Merge pull request googleapis#177 from craigcitro/new_release

Release v1.4.8.

Release v1.4.7.

Merge pull request googleapis#116 from nathanielmanistaatgoogle/master

Release v1.4.6.

Release v1.4.5.