SLIDER-94 Closeable service tests and improvements
SLIDER-94 add tests for WorkflowExecutorService and ServiceTerminatingRunnable; some cleanup of source of rest
SLIDER-94: tests for LongLivedProcess -caught a regression in the switch to ExecutorService based execution
SLIDER-94 ... + tests for ForkedProcessService, change reporting order to avoid service termination before output streams of child process flushed 
SLIDER-94 TestForkedProcessService verifies that an error code is uprated to a service failure
move RPCService in as WorkflowRPCService, add tests, review and update docs ready for copy to hadoop trunk
Merge branch 'feature/slider-94-workflow-services' into develop
Merge branch 'develop' of https://git-wip-us.apache.org/repos/asf/incubator-slider into develop