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/

Coverage: code coverage testing for Python

Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.

For more information, see http://nedbatchelder.com/code/modules/coverage.html