Move the change photo button to photo

Be consistent with the profile view.
Follow users and view user profiles

You can now follow users just like you would follow
projects.  Use the new likeu/ unlikeu/ and countu/
endpoints for 'user'.

You can view other users' profiles by navigating to
/profile/:id where id is the user id number.  This
allows you to click on a user to get more information
about them.

Fix a bug in comment controller.  _.has() doesn't
work correctly on arrays; use instead _.indexOf()

TODO:
- update the user links in comments, etc to navigate
  to the user
- allow users to be pulled up by /profile/:username
  in addition to /profile/:id