Avoid scrollbars in the runner iframe

website/playground/playground-runner.html

@@ -7,7 +7,7 @@
 	<link data-name="vs/editor/editor.main" rel="stylesheet" href="../../release/dev/vs/editor/editor.main.css" />
 
 	<style type="text/css">
-		body { margin: 0; padding: 0; border: 0; }
+		body { margin: 0; padding: 0; border: 0; overflow: hidden; }
 	</style>
 
 </head>