[fix bug 884545] Update mozillians mailing list url.
Merge pull request #517 from hoosteeno/master

[fix bug 880072] Improve layout/fix bugs on group detail page.
[fix bug 884479] Remove settings.MEDIA_URL from RegisterMiddleware when Debug = False
Merge pull request #523 from Sancus/fixmiddleware

[fix bug 884479] Remove settings.MEDIA_URL from RegisterMiddleware when ...
[fix bug 884856] Don't try to register anonymous users.
Merge pull request #520 from glogiotatidis/884856

[fix bug 884856] Don't try to register anonymous users.
Merge pull request #519 from glogiotatidis/884545

[fix bug 884545] Update mozillians mailing list url.