Merge branch 'sync-events-plugin'

* sync-events-plugin:
  Replace EasyMock with Mockito
  Build with API version 2.13
  Fix buck build, remove java_test.source_under_test
  Change docs links to actual file extension (.md)
  Reduce visibility of SyncEventBroker to package-private
  Return proper http status code for unsupported media type
  Handle exceptions when sending error message in servlet
  Stop retrying if thread is interrupted
  Adjust to updated EventDispatcher interface
  Initial version of sync-events plugin

sync-event-plugin branch was created by fetching stable-2.13
(0e602d4bd2938c7b48e7b419abd11511241afbba) branch of repository
https://gerrit.googlesource.com/plugins/sync-events and pushing it to
this repository.

This merge adds the second of the 4 plugins that will be merged in this
repository. evict-cache and websession-flatfile will be done in follow
up commits.

The reason for choosing stable-2.13 instead of master is that the only
commits done in master that are not in stable-2.13 were to adapt to
Gerrit master branch. Since all the sync-events features/bug fixes are
in stable-2.13, use this branch so high-availability will support Gerrit
2.13.

Change-Id: Ifde21b9607acc3aeb34f85ea9f3a560a3991b56d
tree: 315619cde502397904765728a030d0a26ba392df
  1. lib/
  2. src/
  3. .buckconfig
  4. .gitignore
  5. BUCK