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/

"""Multi-consumer multi-producer dispatching mechanism

Originally based on pydispatch (BSD) http://pypi.python.org/pypi/PyDispatcher/2.0.1
See license.txt for original license.

Heavily modified for Django's purposes.
"""

from django.dispatch.dispatcher import Signal