wumpus-basic

Copperbox revision 1586.

Initial work on a Path datatype for Wumpus-Basic.

Wumpus-Core has a path datatype, but this is too limited for drawings. For drawings its necessary to shorten paths - for good drawing of arrow heads; and there are other valuable operations that can't be done on the Core path type - finding the midpoint, finding the angle of the end segments. So a more sophisticated path type is needed.

Wumpus-Core - minor addition vdistance.