Added a User_username table that links the external username with a StatusNet user_id

Added EmailAuthenticationPlugin
Added ReverseUsernameAuthenticationPlugin
Changed the StartChangePassword and EndChangePassword events to take a user, instead of a nickname
User::allowed_nickname was declared non-static, but used as if it was static, so I made the declaration static

plugins/EmailAuthentication/EmailAuthenticationPlugin.php

@@ -0,0 +1,54 @@
+<?php
+/**
+ * StatusNet, the distributed open-source microblogging tool
+ *
+ * Plugin that uses the email address as a username, and checks the password as normal
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   StatusNet
+ * @author    Craig Andrews <candrews@integralblue.com>
+ * @copyright 2009 Craig Andrews http://candrews.integralblue.com
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET') && !defined('LACONICA')) {
+    exit(1);
+}
+
+class EmailAuthenticationPlugin extends Plugin
+{
+    //---interface implementation---//
+
+    function onStartCheckPassword($nickname, $password, &$authenticatedUser)
+    {
+        if(strpos($nickname, '@'))
+        {
+            $user = User::staticGet('email',$nickname);
+            if($user && isset($user->email))
+            {
+                if(common_check_user($user->nickname,$password))
+                {
+                    $authenticatedUser = $user;
+                    return false;
+                }
+            }
+        }
+    }
+}
+