wumpus-drawing

Copperbox revision 2342.

I've updated the library modules to meet the changes to drawing primitives in Wumpus-Basic. I haven't looked at the updating the demos as I'm re-doing some of the objects in Wumpus-Drawing, so the demos can be re-done after this. The drawing primitive changes were actually a side-step whilst I'm re-working the dots in Wumpus-Drawing.

The motivation for changing the drawing primitives is that actually very few things are captured as paths that are either open or closed - perhaps only Paths themselves. Most objects are always closed (e.g Shapes), or always open (Connectors). Thus the dichotomy in drawing is between stroked, filled and filled-stroked, rather than open or closed. This is something present in TikZ but I didn't realize its importance until yesterday.