Add web based python shell to Melange.
It is accessible via http://host/admin/shell url and requires developer rights.
Shell project is part of google-app-engine-samples. This commit moves django configuration from main.py to separate gae_django.py module. Shell project has been modified in order to work correctly with django 1.0+. Build script has been updated and includes shell folder and gae_django.py file.
http://code.google.com/p/google-app-engine-samples/source/browse/trunk/shell/
