IlwisObjects remain in memory

[MartinSchouwenburg]

When cleaning up an ilwisobject the system isnt correctly resetting the counts of contained ilwis objects ( support objects) if there other references of the container ilwis object present. This is logical as the references of the container is correctly removed but as long as there are other references the count of the contained objects will not be reduced. If the last container disappears, the count of the internal objects can be off, preventing a deletion. Probably need to destructor of the container to reset the count of the internal objects.