Refactored job handle factory, added a Hazelcast job handle factory
Abstracted unique id generation (primarily to support clustered unique IDs)
Integration test package and test updates
Introduct clean shutdown on clients, workers and server. Support sending of status updates for workers.
Re-organized the job handle factory
Merged cluster config from sub-module because it didn't make sense to keep it there, future job queue is now a priority queue for better performance.