wumpus

Copperbox revision 2333.

I've removed round_corner_factors from the Drawing Context. I didn't like how this was arbitrarily applied to paths, so I removed it. To add rounded corners back to Shapes etc. I'll probably add extra constructors specifically for round corner version.

Also I've updated the demos in Wumpus-Drawing and updated the code and in Wumpus-Tree. Although the layers above Wumpus-Core are still not readily useful (they would be better off not being on Hackage) it's time the released versions were updated.