rnd-20091124-1-src

rnd-20091124-1-src
* changed internal playfield bitmap handling from playfield sized bitmap
  to screen sized bitmap (visible scrolling area), therefore speeding up
  graphics operations (by eliminating bitmap updates in invisible areas)
  and removing playfield size limitations due to increasing bitmap size
  for larger playfield sizes (while the new implementation always uses
  a fixed playfield bitmap size for arbitrary internal playfield sizes)