[wxPython] on-demand loading of modules

There was a thread, a few days ago, about not importing modules until
they're needed....

I have some code that I've been using to do things related to this in
the Python component of one of my projects;
the code lives in CVS on SourceForge--you can get it by checking out
"pythonmod/loaddir.py" from:

    :pserver:anonymous@cvs.dp2.sourceforge.net:/cvsroot/dp2

... as described at http://sourceforge.net/cvs/?group_id=6996