add test program to intercept VESA BIOS modes and force a mode that
causes VGA raster output of at least 480 scan lines. Because some scan
converters will produce better output that way (going to NTSC), and
because certain VGA capture cards (ahem PEXHDCAP) don't consider a VGA
signal valid unless it has 480 scan lines (never mind the 350- and 400-
line modes every DOS program in existence has been using since 1988!
Argh).