fixed inheritance toggling and line disapperance bugs
Added undo/redo functionality for deleting objects involved in inheritance trees
Merge branch 'mvcDevelop' of bitbucket.org:nul/alphaomega into mvcDevelop
Resolved issue #7: Closing create class dialog with X creates a class with an empty name
Resolved Issue #4: Generated parent class should be undone before child
Added displaying of association labels on diagram, trying to add cardinality but not working presently