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/vehicles/mini.txt

@@ -1,6 +1,13 @@
 # Skids vehicle settings. Lines starting with # are comments.
 # The sprite sheet is mini.png: 32 headings across, 25 tilts down.
 name MINI
+driver ROB
+# yes = towed behind cars (Caravans option) instead of driven
+trailer no
+# The 16 values from the original .set file. Their meaning is not
+# decoded yet, so the game does not use them; the handling below is
+# a reconstruction.
+original 56 24 30 12 3 24 20 12 46 10 100 0 0 0 0 0
 # top speed on tarmac, world pixels per second
 top 190
 # acceleration and braking, world pixels per second squared