Add CRTC properties to the list of Xrandr properties
Fix mouse position when underscan is enabled
Use underscan properties to crop display
Fix reference counting

Now that we re-use the scanout buffer instead of resizing on every mode
switch, fb_bo can == scanout.  in that situation the buffer could theoretically
be deleted by the first dereference.
Merge pull request #2 from ManMower/underscan

Underscan