feature 2027 implemented: the "lost password" feature was rewritten.

The algorithm is highly inspired from WordPress :

1) in a single field, you give a username or an email
2) Piwigo sends an email with the activation key
3) the user clicks on the link in the email (with the activation key) and is able to set a new password

The "lost password" feature is no longer limited to "classic" users:
administrators and webmasters can use it too (no need to tell webmasters
that they can only change their password in the database)


git-svn-id: http://piwigo.org/svn/trunk@11992 68402e56-0260-453c-a942-63ccdbb3a9ee

install/piwigo_structure-mysql.sql

@@ -417,6 +417,7 @@ CREATE TABLE `piwigo_user_infos` (
   `registration_date` datetime NOT NULL default '0000-00-00 00:00:00',
   `enabled_high` enum('true','false') NOT NULL default 'true',
   `level` tinyint unsigned NOT NULL default '0',
+  `activation_key` char(20) default NULL,
   UNIQUE KEY `user_infos_ui1` (`user_id`)
 ) ENGINE=MyISAM;