update polymer, nodebind, and templatebinding

pkg/template_binding/lib/src/input_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 template_binding;
 
 /** Extensions to the [InputElement] API. */
 class _InputElementExtension extends _ElementExtension {
   _InputElementExtension(InputElement node) : super(node);
 
   InputElement get _node => super._node;
 
   Bindable bind(String name, value, {bool oneTime: false}) {
     if (name != 'value' && name != 'checked') {
       return super.bind(name, value, oneTime: oneTime);
     }
 
     _node.attributes.remove(name);
     if (oneTime) {
       _InputBinding._updateProperty(_node, value, name);
       return null;
     }
 
-    _self.unbind(name);
-    return bindings[name] = new _InputBinding(_node, value, name);
+    // Note: call _updateBindings to always store binding reflection, because
+    // checkboxes may need to update bindings of other checkboxes.
+    return _updateBindings(name, new _InputBinding(_node, value, name));
   }
 }