Improve the map descriptions

[stevecotton]

Add some extra comments to the map descriptions, about the difficulty and which are the best ones to start with.

Prompted by thinking that Spooky Forest should be labelled as expert.

[stevecotton]

Rush: one where you need to know the map, and how it changes.

System has one unfair trap, that isn't hinted.

There are hints in the windmills on Trapped, but it could do with a hint that there are hints there.

[Jordy-Jordan]

agree