Add vsync swapbuffers. This waits on the irq so gears run in this mode

Add vsync swapbuffers.  This waits on the irq so gears run in this mode
will have a very low cpu utilization (and also a very low framerate).

Fix up the pageflipping code.  This works now but is totally oblivious
to the X server (ie. it works but it's broken).  Turned off by a #define.