Merge pull request prometheus#575 from prometheus/beorn7/release

Cut 0.12.0.

Merge pull request prometheus#564 from prometheus/beorn7/release

Cut release 0.11.1

Cut release 0.11.0.

Merge pull request prometheus#472 from prometheus/beorn7/release

Cut release 0.10.0.

Merge pull request prometheus#464 from prometheus/beorn7/release

Prometheus version 0.9.0.

Prometheus version 0.9.0rc5.

Prometheus version 0.9.0rc4.

Prometheus version 0.9.0rc3.

Merge pull request prometheus#426 from prometheus/u-c-l/bump-version

It's time for 0.9.0rc2.

Bump VERSION to 0.9.0rc1.

Change-Id: Ie1a02d026290e9ecee83990b7baa2cd730df6869