code review & cleaning

[alex]

As we discussed yesterday, we need to review code to make it:

1. Use same style for the code (this means following http://www.djangoproject.com/documentation/contributing/#coding-style)
2. Use same style for function & variable naming
3. Adding documentation in code. Document model fields (since we sometimes forget ourself what is for)
4. Document djwarehouse architecture
5. Document how to extend via OneToOne fields
6. Document which patches needs to be applied to Django