wumpus-basic

Copperbox revision 1763.

I've added a DirectionContext monad - this is a reader monad with line direction as the context. Its intended to make creating paths easier when the path needs displacing by a line angle. For instance, arrow tips are easy to think about if drawn on a left-to-right horizontal line, its more complicated to think about them on a line of some parametric angular direction. DirectionContext abstracts the direction and provides two morphisms perpendicular and parallel that are analogous to the vector constructors vvec and hvec.