Add the contents of disk 1

- LHA -lh5/-lh6/-lh7 decoding with CRC checks (disk 1 is mostly lh5)
- Real track palettes and set names, read from each track file's header
- Camaro, plus the caravan as a towable trailer (Caravans option)
- Drivers' names, menu pictures and the original .set values per car
- Original sound effects (IFF 8SVX) through a new sample mixer: engine
  pitched with revs, tyre screech, crashes, backfire, horn, start beeps
- The original tune (OctaMED MMD1) through a new player; loudness tracks
  OpenMPT's render through the whole song. Music option in the menu
- Title picture (IFF ILBM) at the top of the menu
- skids unpack and skids music commands
- Gate crossings now judged on each car's whole movement per frame,
  including collision knocks; stalled computer cars are put back on the
  line after 8 seconds

The executable's game logic (handling, AI) is still not decoded.

assets/tracks/track4-1/track.txt

@@ -37,6 +37,9 @@ gate 402 504 402 378
 gate 342.53125 501.71875 264 374.5
 gate 316.5625 513.03125 192.25 387
 
+# Name of the set of tracks this one belongs to, shown in the menu.
+set Sounf Of Speed
+
 # As stored in the original data; not used by the game.
 start 213 275
 flags 1