Adding CircuitBreaker class -- not yet used
Initialization done in the constructor instead of the init method
Changing CachingRMInvoker from a singleton to being initiated from the ModuleStarter
Fixing some bugs in the CircuitBreaker
CachingRMInvoker now uses the CircuitBreaker to call RM
Removing unnecessary init method from IsAliveServlet
Mixing two changes.  Renaming ...ReceptModuleInvoker + optionally file logging (good for testing)
Optional file logging now a config property and disabled for tests
CircuitBreaker timeout and threshold now in config