Zotero.Utilities.varDump(): Set maxLevel for all Nodes/Windows (zotero#22)

Fixes varDump() practically never returning when called on `document` in the
browser or on a node from another frame.

Author: AbeJellinek

utilities.js

@@ -1480,6 +1480,10 @@ var Utilities = {
 				level = maxLevel;
 			}
 		}
+		// Do the same for cross-context Node and Window objects
+		if (obj.hasOwnProperty('nodeType') || objType === '[object Window]') {
+			level = maxLevel;
+		}
 
 		// Recursion checking
 		if(!parentObjects) {