make in-place update functionality (over the same DRE)

[GoogleCodeExporter]

Implement an update.py script (optionally with wx gui) that will update only 
the DeVIDE python code given a certain base DRE.

So for example DeVIDE 9.8.3784 can be updated with a DeVIDE 9.8.xxxx, that 
comes from a NEW branch (v9-8-a, b, c and so forth).

Original issue reported on code.google.com by cpbotha on 23 Apr 2010 at 8:38