PROBCORE-425 Implemented forward, back, and random for Events View.
PROBCORE-437 Replaced internal Collection of AbstractElement with ModelElementList. Refactored all classes that this affects (it was a lot of classes)
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	de.prob.core.kernel/src/main/java/de/prob/web/views/BMotionStudioSession.java