[PyCrust] Module names shortened in 0.5.2

[Patrick K. O'B. <po...@or...>]

Prompted by Robin, I have shortened the PyCrust module names in version
0.5.2 (currently under development and available only on CVS). The new
module names:

shell.py, editor.py, interpreter.py, version.py

I also changed the constant in version.py from "version" to "VERSION".

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Patrick K. O'Brien
Orbtech
"I am, therefore I think."