todo:

major:
- DJGPP support
- fakemodes (most likely in a VGA class or something)

minor:
- optimise banked mode console updates
  (don't copy the entire screen)
- centre screen when no exact match for the requested mode can be found
  (done for linear modes, won't be done until banked mode console updates
   are optimised...)

most likely lasting for the rest of time:
- vbe bugfixes
