wumpus-basic

Copperbox revision 2397.

I've re-introduced a distinction at the type level between queries - just an answer wrt. the Drawing context - and images - graphic output and an answer wrt. the Drawing context.

This introduces some overhead as the "regular" objects (Image, LocImage, Connector...) effectively now have two definitions and instances for Functor, Monad etc. but it does seem semantically clearer.