Add ability to make an online display active or deactivate a display

[jhford]

It'd be neat to be able to turn a display that is plugged in but off on, or an active display off.

screenresolution 800x600x32 off -should turn display 0 to 800x600x32 -should deactivate display 1 screenresolution off 800x600x32 -should deactivate display 0 -should set display 1 to 800x600x32 screenresolution skip off -should skip display 0 -should deactivate display 1