Don't overdraw selected edges.
Fix crash in MapTreeView

If the tree view is only notified when objects will be deleted, it will still return those objects as children when the tree view updates itself, leading to stale entries in the tree view. Therefore, it has to be notified only after the objects have been deleted. Since we still need the parents to update the tree view, the objectsWereDeletedNotifier now takes an ObjectParentList instead of an ObjectList.,
Remove log messages from tree view
Improve accelerator table update when focus changes.
Don't crash in vertex tool when incident side has > 4 vertices.

The face chopping algorithm did not account for the number of vertices of the face being chopped changing as a result.
Use Shift+Click to merge vertices in vertex tool.