Refactoring done

 - `FutureMock` and `FutureCallableMock` are now inherited from `Future`. Because of this, signature of `bind` method slightly changed - now errorback parameter is optional
 - check application tests fixed. It fails because of application exists with error code (default behaviour)
 - tools_sync.py file has been removed cause noone use it
 - chunker example application added. It uses multiple responses from application to client
 - now cocaine-tool has author