sort twill-yarn test runners, add missing tests

Signed-off-by: Terence Yim <chtyim@apache.org>
Make PlacementPolicyTestRun more robust.
(TWILL-110) added state guard to prevent possible race-condition when shutting down zk client, which causes deadlock.

Signed-off-by: Terence Yim <chtyim@apache.org>
(TWILL-100) Fix examples POMs and update documentations
- Updates to examples
- Updates to BundleJarExample application and documentation.

Signed-off-by: Terence Yim <chtyim@apache.org>
Temporarily disable Travis-CI hadoop-2.3 profile as it always fail due to hostname issue. Looks like it is a known issue (https://github.com/travis-ci/travis-ci/issues/2970)
Merge branch 'master' into site

Conflicts:
	src/site/markdown/GettingStarted.md