Fix saving project to XML file
Basic reading of the XML file working
Able to read Diagrams and Classes
Properly set diagram name
Handle reading of all Element types
Merge branch 'undo_redo_memento'

Conflicts:
	src/WackaUML/ProjectController.java
Add cut/copy/paste functionality.
I created a new Edit menu in the GUI. There are new buttons in the edit menu for each operation.
Each operation calls the same ID in the Diagram controller.
The diagram controller gets the currently selected items from the WContext.state.getChildren function which is based on selected elements.

I changed WState from an interface to an abstract class so I could have a default getChildren that returned an empty set.
Added delete option to edit menu.
Corrected issue where the movingAdapter for classes and relationships was still pointing to the copied element when pasting.
Properly clone elements on paste.
Merge pull request #26 from Zedzap/copy_paste

Copy paste
Undo redo limits

Added a limit of 10 undo/redos
Prevented undo/redo from being called if the stacks are empty
Fixed undo redo red color bug

Fixed bug where performing a redo causes the last moved class to be
drawn as red