wumpus-basic

Copperbox revision 1729.

Some more work on Chains, plus I've added a field for line spacing to the the drawing context.

The line spacing is actually its a scaling factor of the point size - 1.2 times the point size turns out to be a good factor. With this in place I've been able to add a graphic primitive for multi-line text labels, Wumpus-Core originally had a function for this but it got lost as the Picture Language module got punted about.