1) Remove zookeeper 3.4.3 dependency from merger
Merge branch 'master' of github.com:metamx/druid
fix NPE for master balancing; introduce max number of workers for indexing service
Merge branch 'master' of github.com:metamx/druid
[maven-release-plugin] prepare release druid-0.3.28
[maven-release-plugin] prepare for next development iteration
Merge branch 'master' into stop_task

Conflicts:
	merger/src/test/java/com/metamx/druid/merger/coordinator/RemoteTaskRunnerTest.java