MDL-21249 improved php docs and adding direct access prevention in core libs

lib/rsslib.php

@@ -18,11 +18,14 @@
 /**
  * This file contains all the common stuff to be used in RSS System
  *
- * @package   moodlecore
- * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
- * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @package    core
+ * @subpackage rss
+ * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
+defined('MOODLE_INTERNAL') || die();
+
  function rss_add_http_header($context, $componentname, $componentinstance, $title) {
     global $PAGE, $USER;
     $rsspath = rss_get_url($context->id, $USER->id, $componentname, $componentinstance->id);