Added RequestNotFoundListener to addListenerIfPending method
you can now be notififed when the request doesn't exist
As per Stephan's comments, made PendingRequestListener and added a method to SpiceManager to access it
Refactored RequestProcessor
Create RequestRunner class from the RequestProcessor class
Extracted Progress Reporting code so that it can be extended
Moved the new classes into reporter and runner packages
Moved classes from request.runner package back into the request package due to access in CachedSpiceRequest
Merge branch 'improve-add-listener-if-pending' into refactor-request-processor_plus_improve-add-listener-if-pending

Conflicts:
	robospice-core-parent/robospice/src/main/java/com/octo/android/robospice/request/RequestProcessor.java
Updated changelog