convert UndoManger to exports style

editor.html

@@ -158,20 +158,19 @@ require(
         htmlMod,
         xmlMod,
         textMod,
-        UndoManager
+        undoMod
     ) {
 
 var event = eventMod.event;
 var Editor = editorMod.Editor;
 
-
 var Document = docMod.Document;
 var JavaScriptMode = jsMod.JavaScript;
 var CssMode = cssMod.Css;
 var HtmlMode = htmlMod.Html;
 var XmlMode = xmlMod.Xml;
 var TextMode = textMod.Text;
-
+var UndoManager = undoMod.UndoManager;
 
 var docs = {}