Thread safe callbacks from Service system will not give access to Run, LuminosityBlock or Event

Given there is no way for a Service to register what it would read from a Run, LuminosityBlock or Event, it is not safe to give access to those objects to Services.
Merge pull request #815 from Dr15Jones/doNotGiveServicesAccessToEvent

Thread safe callbacks from Service system will not give access to Run, LuminosityBlock or Event