provide fullpaths while import

Author: Amrita1991

model/comment.class.php

@@ -26,8 +26,8 @@
 require_once($CFG->dirroot . '/mod/pdfannotator/lib.php');
 require_once($CFG->dirroot . '/mod/pdfannotator/locallib.php');
 require_once($CFG->libdir . '/completionlib.php');
-require_once('model/annotation.class.php');
-require_once('model/pdfannotator.php');
+require_once($CFG->dirroot . 'model/annotation.class.php');
+require_once($CFG->dirroot . 'model/pdfannotator.php');
 
 class pdfannotator_comment {