Merging dart:html interfaces and implementations

lib/html/templates/html/interface/interface_Element.darttemplate

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // WARNING: Do not edit - generated code.
 
 part of html;
 
 /**
  * All your attribute manipulation needs in one place.
@@ skipping 31 matching lines @@
   bool toggle(String token);
 
   /**
    * Returns [:true:] classes cannot be added or removed from this
    * [:CSSClassSet:].
    */
   bool get frozen;
 }
 
 $!COMMENT
-abstract class Element implements Node, NodeSelector {
+abstract class _IElement implements _INode, NodeSelector {
   factory Element.html(String html) =>
       _$(ID)FactoryProvider.createElement_html(html);
   factory Element.tag(String tag) =>
       _$(ID)FactoryProvider.createElement_tag(tag);
 
   AttributeMap get attributes;
   void set attributes(Map<String, String> value);
 
   /**
    * @domName childElementCount, firstElementChild, lastElementChild,
@@ skipping 46 matching lines @@
    * `extend Element` from your class, in which case this field will be
    * deprecated and will simply return this [Element] object.
    *
    * [wc]: http://dvcs.w3.org/hg/webcomponents/raw-file/tip/explainer/index.html
    * [x-tags]: http://x-tags.org/
    */
   var xtag;
 
 $!MEMBERS
 }