The tracks left by hero were cleared when player saved and
restored the game, or changed levels. Now the tracks are
saved in the dungeon level, so changing levels keeps the tracks
left by hero in that level.
Also increased the length of tracks from 50 to 100, and
simplify the tracking function.
Thing not done: fade out old tracks when returning to a level.
Breaks saves and bones.
I'll push a formatting guide at some point. There may still be
outstanding changes, but please feel free to resolve those as you arrive
a them.
To the best of my knowledge, there is no changes to the actual code
content, but the formatter does have the occasional bug. If you run into
an issue, please fix it!
