An action to delete your own account

The new DeleteaccountAction lets a user delete their own account
(subject to global rights set by the admin). It presents a form to
delete the account, with an "I am sure." text entry box.

It then schedules the account for deletion and logs the user out.

lib/router.php

@@ -200,6 +200,7 @@ class Router
                           'geocode',
                           'version',
                           'backupaccount',
+                          'deleteaccount',
             );
 
             foreach ($main as $a) {