[PythonCAD] Code changed to use super()

[Art Haas]

Hi.

The first batch of changes to using super() when calling parent class
methods is now finished, and the code is available on the public
repository. I think I've changed nearly all the calls, but there are
probably a few that have slipped by. I found and fixed a couple of bugs
while making these changes, as well as reworking some of the code in
places. Various classes defined in 'tools.py' were modified so the class
hierarchy would be clearer, for example.

Anyone running PythonCAD under Python-2.4 yet?

Art
-- 
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