cosign_auth

I have taken the cosign module and created a "cosign_auth" module that works on Drupal 7. This module is not dependent on the webserver_auth module and does not use or rely on the authmap table. It is based on the following presumptions:

* You either use cosign for authentication or you don't
* normal Drupal roles/permissions are used for authorization, thus restricted access to the site requires the user to be added the normal Drupal way. The password provided when adding a Drupal user is never used unless the cosign_auth module is disabled/removed.
* the Drupal "super-user" with UID=1 should be a valid cosign uniqname (I manually changed this "name" in the "users" table for UID=1 using phpmyadmin for existing Drupal sites)
* the "normal" login & logout buttons/paths are used.