Renamed navigation.py to mousing.py
Added a "mouse" tab to preferences dialog
Implemented button to remove mouse handlers in preferences
Made remove and configure insenstiive until there is a selection
Implemented Add/Cancel page movement in mouse preferences tab
Implemented adding mouse handlers
Some styling changes
Implemented dialog for changing the button of mouse handlers
Added DragHandler and HoverHandler settings widgets
Implemented spin mouse handler settings widget
Implemented stretch handler settings widget
Added code to automatically select a newly added mouse handler
Fixed image view layout not disconnecting from a view when there is layout change
Fixed wrong degrees-to-radians calculation (I'm terrible at trigonometry)
Implemented scroll handler settings widget
Created MouseHandlerPivot object
Implemented scroll to zoom settings widget
Implemented scroll to spin settings widget
Added code to modify mouse handlers nicknames
Now handles delete key press and double click