introduced abstract class that implements equals, hashcode and getCode for all Evaluation elements (PROBCORE-284)
minor fixes
pushed list of states to graph class (PROBCORE-284)
Use long instead of BigInteger (PROBCORE-284)
- Implementation is simpler and we do not expect to get too many states for a long value
made evaluateFormulas a private method (PROBCORE-284)
simplified toString (PROBCORE-284)
merge
Merge remote-tracking branch 'origin/develop' into feature/ss_refactoring
renamed methods

removed stuff
Merge remote-tracking branch 'origin/develop' into feature/ss_refactoring

Conflicts:
	de.prob.core.kernel/src/main/java/de/prob/animator/domainobjects/EventB.java
Merge branch 'feature/ss_refactoring' into develop