Changed version to 0.12.1 in configure.ac.

Fixed issues from cherry-picks for 0.13.0-rc4.

Changed slave command line flag 'safe' to 'strict'.

Review: https://reviews.apache.org/r/12084

0.12.0 Release

Updated CHANGELOG for 0.13.0 (rc2).

Tag for 0.12.0-rc1.

Added a new 'statistics.json' endpoint to the ResourceMonitor, this

deprecates the old usage.json endpoint.

This is v2 of the monitoring statistics, added with a new 'statistics.json' endpoint.

The 'usage.json' endpoint is now deprecated, and will be removed at a later point.

From: Ben Mahler <benjamin.mahler@gmail.com>
Review: https://reviews.apache.org/r/11641

Tag for release-0.11.0-incubating-RC3.

Tag for release-0.11.0-incubating-RC3.

Tag for release-0.11.0-incubating-RC2.