Demo conservative ZK assignments (lots of logging)
Added smart assignment-refreshing for workers.
Merge remote-tracking branch 'community/master' into community-zk-assignments
Cleaned up and ready for pull.
Cleanup for pull
One more bit of cleanup
Keeping version data only in memory, as part of supervisor and worker structures.
Merge branch 'community-zk-assignments' of https://github.com/knusbaum/incubator-storm into STORM-375

STORM-375: Smarter downloading of assignments by supervisors and workers
Added STORM-375 to Changelog