[PythonCAD] Latest changes in repo

[Art Haas]

Hi.

The latest batch of changes in the repository deal with removing the
usage of unbound method calls. These were used in the messaging system
for the connect() method. Previously, connect() was called with three
arguments:

connect("message", obj, class.method)

Argument 'message' was a text string, and 'obj' was an object that would
execute the 'class.method' method. Now, connect() is called with only
two arguments:

connect("message", bound_method)

This change required reworking the internal bits of the Messenger class,
but the other methods are still the same. In addition to simplifying the
code, the use of a bound class method is, I feel, more "pythonic".
Incidentally, calling connect() with two arguments is similar to how the
GTK signal system invokes a similarly named function.

I've got a few more number of changes I want to make before the next
release, so there may be a release at the end of the month. One of the
goals for this year is to make more frequent releases. A bi-weekly release
would not be common, but at least one a month sounds good right now. The
work on planned interface changes will start shortly, and the recent
changes of using super() and the connect() change above are good
internal improvements.

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