[FLINK-1019] Implementation of akka based RPC system

Replaced the old Nephele RPC service with akka based system. Thus, several components are now implemented as actors. This includes the JobManager, TaskManager, MemoryArchivist, JobClient. The legacy RPC service and the corresponding protocols are removed. 

Replaced also the execution service of the ExecutionGraph by akka's futures to unify the system. 

Removed the LocalInstanceManager whose task is now handled by the InstanceManager. The responsibility to create local task managers is now delegated to the FlinkMiniCluster. 

The EventCollector was removed and the respective event classes. The events are now directly sent to the respective listeners. 

Moved the resources of the WebInfoServer and the WebInterfaceServer to the resource folders of the corresponding projects. As a consequence these resources are bundled with the jars and directly served from them by Jetty. 

The yarn client was adapted to communicate with the actors. The former ApplicationMaster is combined with the JobManager to simplify the system. The uber-jar is now created with maven's shading plugin.

Since this is a big change I would be happy if another pair of eyes could take a look at it.
Really good point Ufuk. Thanks for spotting the resource leak. I'll fix it.