Login fixes
* Now remember the currently logged in user, including his "real name"
* So no longer need force_login, we can tell if the reqested user ==
  current user
* force_navigate no longer needs to assume admin user when browser is
  restarted (it can just use current_user which stays remembered when we
  kill the browser).
Give current_user initial value
Merge pull request #873 from weissjeffm/login-fixes

Login fixes