Using e4 events instead of listeners.
Fixed NPE
Merge branch 'master' of https://github.com/aradouan/ReqCycle.git

Conflicts:
	plugins/org.eclipse.reqcycle.jdt/src/org/eclipse/reqcycle/jdt/handlers/JDTReachableHandler.java
	plugins/org.eclipse.reqcycle.sesame/src/org/eclipse/reqcycle/sesame/handlers/SesameHandler.java