BROKEN - Add browserid verify class and new-user form

This adds the initial bits for creating a new-user form. This kicks in
after you've logged in with a new account.

FIXME - Doesn't work, yet. For some reason the verify class isn't
getting called.
Show email instead of username

django-browserid creates "interesting" usernames. We could write our own
username generation function or have a profile page or a number of
things, but it's easier to just show the email address for now.