Track and exploration

[kjartan]

Sloth now tracks which rooms you have visited. If you visit every single (reachable) room in an area, the track skill will give you (and anyone following you) reduced movement costs in that area, as you use your superior knowledge to pick the best shortcuts.

We will probably be adding more stuff that depends on exploring certain areas, like autoquests, boards that show how much of the world you have visited, etc.