wumpus-basic

Copperbox revision 1551.

Check-pointing the first prototype of dots with anchors - which are needed for drawing trees, etc.

This version makes heavy use of GHC extensions to encode different dots with different anchor calculations at the same existential type. I'll most likely change it so that anchor-dots can be of different types, but support a common class for drawing like the shapes in Wumpus-Shapes.