Interactivity Feature & Bug fixes

- Bugfix Node Information. Jumping to the selected nodeclass within the
dialog should now work corretly.
- Nodewidth is now computed correctly for every graphclass.

- Deletion of Nodes implemented. A node is not just deletet, every edge
is calculated anew, so that the graph will reflect the proper
dependencys.

- Add Super/Subclasses to the graph depending on selected graphClasses.
Interactivity Fix

prohibit the computation for equivalent classes when one of the
equivalenceset has been processed.

Fixes the bug that there are 4 Arrows between 2 Classes if one of them
has 4 equivalence classes.

Fix 2:
Compute the dependencytree from scratch.
Deleting two nodes that have the same single superclass and the same
single subclass results in a single arrow from super to sub instead of 2
arrows.