* Write a function to instantiate FriendlyFormPlugin from a Paste Deploy
  config file.
* Write a FriendlyFormPlugin-based form which only uses post-login and
  post-logout pages, and doesn't use the __logins query string argument.
* Add the ability for FriendlyFormPlugin to use cookies instead of the
  "came_from" and "__logins" arguments (http://bugs.repoze.org/issue59).
