fix 2682, add extra check for already ready DOM

add a `if (!ready) check();`  for cases when MooTools is added to a page
that is already loaded.

Author: SergioCrisostomo

Source/Utilities/DOMReady.js

@@ -77,6 +77,7 @@ if ('onreadystatechange' in document) document.addListener('readystatechange', c
 else shouldPoll = true;
 
 if (shouldPoll) poll();
+if (!ready) check();
 
 Element.Events.domready = {
 	onAdd: function(fn){