logging headers (outgoing) in debug mode
important user lib changes

- instead of sending form data via the port wire to the user lib which
  does custom XHR requests, the user_panel.port is now wrapped in
  xhr_wrapper
- login/join now call the user model functions test_auth/join directly
  from the user panel script. this gives a cleaner, more direct method
  to test auth and join
- on login/join success, the panel sends a success eevent with necessary
  login info. works great.