Support Django 1.5.

- Include quotation marks around view_name in template tags.
- Fix adminmedia and admin_media_prefix.
- Replace uses of 'redirect_to', which was deprecated in 1.5, with RedirectView.
Pylint.

This enables the use of "symbolic ids of messages in [pylint] output" which was
introduced in 0.25.3 and is more user-friendly than using ids.