Initial branch for using Akka clustering library to add clustering support
Centralized configuration
Minor changes to clustering.
Cleanup
Embedded worker, client, cluster with HBase and ZooKeeper support, cleanup, re-org

Limit the number of snapshots to 2880
Fix a bug in the uptime calculation
Update configuration files to support persistence engines, load existing jobs when starting up.
Dependency conflict resolution to remove slf4j-log4j12
Updated interface implementations for ZK JobQueue