use JEBEventServiceIsolator.PopEvent(...) in JEBEventService

[Torsten Schmidt]

Add method PopEvent?(...) to JEBEventServiceIsolator and use it in JEBEventService instead of directly retrieving an event from the event service. it's working like it is done, but with using the isolator, one decouples the event service much better. Note: the event serice may not be threadsafe.