Add a restructuring of the user profile page

There are some issues still to be resolved:

 - The "view all annotations for a user" link has nowhere to
   go to - a new view needs to be added.

 - The mockup doesn't include the <div id="user_public_banned">
   with the message if a user is banned, so that may not be
   in the right place or structured correctly.

 - The user profile photo isn't explicitly in the page, and
   probably should be.

 - If it's not your page, there used to be a "Sign in to change
   password, subscriptions and more (Mark Longair only)" link
   and that's not in the mockup - it's not clear if that should
   still be present or not.