[PythonCAD] Various drawing updates at repo

[Art Haas]

Hi.

I've sent some changes up to the public repo that address various redraw
issues I'd found since the last release. The biggest problem I'd seen
dealt with highlighting Point entities and handling the various cases
when the Point was shared with various entities and one of the entities
moved or was deleted. I think the problem has been fixed, and the
fix enabled me to cut down on offscreen drawing calls so a slight
speedup also emerged. A few other tweaks also are in the repo.

The changes are just an 'svn update' away for anyone accessing the code
with Subversion.

Art Haas
-- 
Man once surrendering his reason, has no remaining guard against absurdities
the most monstrous, and like a ship without rudder, is the sport of every wind.

-Thomas Jefferson to James Smith, 1822