[162] Add implicit constraint

This commit checks for another implicit constraint, namely following combination
of processes is being prevented:

AnyProcess -> DecisionNotSpecified -> Merger -> AnyProcess

Also some code lines in the event handler 'AfterCreateModelingConnector' have been
reduced by creating two PROCEDURE's (i.e., GET_NEXT_OBJECT and GET_CLASS_NAME_BY_ID)
and therefore facilitating reuse.
Merge branch 'feature-162' into develop