Converted Note to UIPanGestureRecognizer

Logically, it makes the code clearner. However, it doesn't really
change the functionality of the preexisting code (sadness).

Reason:
 * Before: three lines used to create and add UIPanGestureRecognizer to
UILabel
 * After: three lines used to assign UILabel to Note which was
converted into a UIPanGestureRecognizer (redundant)

I also added the code to delete Actor we added together at the last
minute before the presentation. I guess I'll play around with the
SettingsView to see if I can set the stage dimensions/make it look
neater.