River Raid

Patched by TLR.
- clean crack from the original Activision tape release.
- remapped both players to joystick 2.
- remapped keys to A/B/C/D (both DTV buttons and keyboard keys)
- retimed raster interrupts slightly to make it work correctly on NTSC.
  (still some minor color flickering on both PAL and NTSC)
- runs on a c64 too.
