add "mp3" (used by DewPlayer) to the list of query string parameters …

…to search for when converting relative urls to absolute urls

mod/hotpot/lib.php

@@ -1849,7 +1849,7 @@ function hotpot_convert_relative_url($baseurl, $reference, $opentag, $url, $clos
     }
 
     if ($query) {
-        $search = '#'.'(file|src|thesound)='."([^&]+)".'#ise';
+        $search = '#'.'(file|src|thesound|mp3)='."([^&]+)".'#ise';
         $replace = "'\\1='.hotpot_convert_url('".$baseurl."','".$reference."','\\2')";
         $query = preg_replace($search, $replace, $query);
     }