added iframe to $bad (#3380)

iframe can't be rendered in feed reader, so we can delete it

bridges/GolemBridge.php

@@ -114,7 +114,7 @@ class GolemBridge extends FeedExpander
 
         // delete known bad elements
         foreach (
-            $article->find('div[id*="adtile"], #job-market, #seminars,
+            $article->find('div[id*="adtile"], #job-market, #seminars, iframe,
 			div.gbox_affiliate, div.toc, .embedcontent') as $bad
         ) {
             $bad->remove();