wumpus-basic

Copperbox revision 2245.

I've changed affine transformations to be monomorphic, operating only on Images and Graphics (Graphic is a special case of Image).

This is quite a radical step - while it makes Wumpus less expressive, it does make a lot of sense. Now affine transforms are can only be performed on things that are tangibly within an affine frame. Previously, a LocImage could be transformed even though it isn't really an affine object until it's placed with the `at` operator.

Pragmatically, limiting the affine operations to a single type removes the all the problems with the affine type classes and their horrible contexts to enforce units. That said, Wumpus still needs helper classes for transformations in Wumpus-Core (the DRotate family) and it currently has the CtxRotate family of classes, though the latter might be replaceable as they are just functorial operations.