Cleanup - remove old code and files
Define language in tests
Update multilingual flatpages

 * We also had to rename flatpages application to 'mlflatpages' to avoid
   conflict in application names.
Fix styles in administration
Update documentation
Update and fix tests

 * Add French to test setup.
 * Refactor tests to be independent on language settings of used
   settings module.
Update function to make language code safe
Refactor tests
Update sanitize language codes in models
Remove logging fallback import
Remove obsolete form factory overrides

 * Remove obsolete factories for multilingual forms.