- plugins: added new action user_init

- put in a new admin_multi_view:allows admins to change on the fly language/theme and view gallery as guest (useful for developers and just to show a 'new' way of using plugins)
- removed some warnings from history.php and increased table width to 99%
- remove unused admin language strings

git-svn-id: http://piwigo.org/svn/trunk@1821 68402e56-0260-453c-a942-63ccdbb3a9ee

include/user.inc.php

@@ -74,4 +74,5 @@ $user = build_user( $user['id'],
           ( defined('IN_ADMIN') and IN_ADMIN ) ? false : true // use cache ?
          );
 
+trigger_action('user_init', $user);
 ?>