Issue #1625 body class definition in section init

Initialize body_classes in common.inc.php
Add class for section and section id
also add class with search id
Class is added to $page in section_init now
Also add tis info to the body dataset for javascript use

include/common.inc.php

@@ -51,6 +51,7 @@ $page = array(
   'errors' => array(),
   'warnings' => array(),
   'messages' => array(),
+  'body_classes' => array(),
   );
 $user = array();
 $lang = array();