Fix for bug: SheepShaver compiled with VOSF off will not display
fullscreen on OS X. The VM boots, but the display is entirely black.
This was expected, I suppose, since video_refresh_dga() didn't
actually attempt to draw anything!
The patch fixes this. Notes:
* video_refresh_window() now takes an argument of type driver_base,
since nothing specific to driver_window was used
* video_refresh_dga() can now call video_refresh_window_static()
* update_display_static_bbox() now respects the destination having a
different bytes-per-row from the source
* fullscreen modes are now created for all depths