feature 2703: make it easy for plugins to add tabs in admin screens

add a trigger a give an id to each core tabsheets

git-svn-id: http://piwigo.org/svn/trunk@16925 68402e56-0260-453c-a942-63ccdbb3a9ee

admin/batch_manager.php

@@ -379,6 +379,7 @@ else
 if (in_array($page['tab'], $tab_codes))
 {
   $tabsheet = new tabsheet();
+  $tabsheet->set_id('batch_manager');
   foreach ($tabs as $tab)
   {
     $tabsheet->add(