Bump up Django requirement: Bit missed in c17660f8
Requirements: This version contains improvements to MySQL support

See http://pytest-django.readthedocs.org/en/latest/changelog.html#id2

Also this aligns us with Evernote.
Requirements: Document places where Django required version must be updated
Bugfix for unset variable
Permissions: Fix a profile join I missed
Move signals out of pootle_app models
Cleanup: Move form out of view
Random cleanups
Permissions: Fix Project.for_username() to work with User
statistics: Use a foreignkey to User instead of PootleProfile