EntityManager autocommit, Update build scripts, Cluster API cleanup

* Adding autocommit feature to DefaultEntityManager.  When set to true this feature will commit before returning from any call.  When set to
false, multiple persistence calls are added to a ThreadLocal mutation
batch which will only be executed when 'commit()' is called.
* Change default compaction_strategy for queue to SizeTiered
* Add schema agreement precheck to Cluster client interface prior to
making schema changes.
* Update gradle build files