Replace non-ASCII apostrophes with ASCII ones for l10n.
Fix Bug 848000: Finish hooking up demodalized upload process.

- Removes excess code leftover from modal upload, such as complex 
  login button logic and the extra view for launching Persona login
  from within the modal frame.
- Adds a "requires-auth" class that will ensure the user is logged in
  vía Persona before letting them follow the link.
- Update to latest django-browserid.