First pass at adding ZooKeeper integration code contributed by Aswin Raveendran.
Added zookeeper cloud start sequence diagram.
Merge branch 'master' into tomk-zk

Conflicts:
	docs/uml/Makefile
Add back .md file for plantuml.
Make requirement Java 1.6 instead of 1.7.
Started implementation with raw zookeeper.
More implementation for raw zookeeper.
More zookeeper changes.
Merge branch 'master' into tomk-zk
Default help for -jar.
Make help default -jar class to run.
More interaction with Zookeeper.  Workers now register themselves.
Still need to implement the flatfile generation.
Remove curator.
Added ZooKeeperFactory.
Now able to create a cloud.
doWait now works.
Merge branch 'master' into tomk-zk
Add gradle wrapper.
Add wrapper jar and properties.
Disallow override_with_best_model from the GUI if n_folds != 0.
Add scalability.png for DL vignette.