[repo creation] removing existing entities of 'single' cardinality relatino should be considered as 'activeintegrity' hook. Also don't disable that category during repo creation to avoid pb such as two default workflows for one entity types

merge

handle Service Close request correctly (closes #736039) The windows event self._stop_event was not used, and twisted was not getting a chance of terminating cleanly by calling its shutdown event handlers (which would eventually call pyro_unregister). Fixed by calling reactor.stop()