Rename mdv -> template_binding, remove experiemntal apis from dart:html

pkg/mdv/lib/src/text_area_element.dart

-// Copyright (c) 2013, 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.
-
-part of mdv;
-
-/** Extensions to the [TextAreaElement] API. */
-class _TextAreaElementExtension extends _ElementExtension {
-  _TextAreaElementExtension(TextAreaElement node) : super(node);
-
-  TextAreaElement get node => super.node;
-
-  NodeBinding createBinding(String name, model, String path) {
-    if (name == 'value') {
-      // TODO(rafaelw): Maybe template should remove all binding instructions.
-      node.attributes.remove(name);
-      return new _ValueBinding(node, model, path);
-    }
-    return super.createBinding(name, model, path);
-  }
-}