Change how events are handled in Effen

sky/framework/components/radio.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import '../fn.dart';
 import 'button_base.dart';
 import 'material.dart';
 
 typedef void ValueChanged(value);
 
@@ skipping 32 matching lines @@
     border-radius: 5px;
     background-color: black;
     margin: 2px;'''
   );
 
   Radio({
     Object key,
     this.onChanged,
     this.value,
     this.groupValue
-  }) : super(key: key) {
-    events.listen('gesturetap', _handleClick);
-  }
+  }) : super(key: key);
 
-  Node build() {
-    return new Material(
-      style: highlight ? _highlightStyle : _style,
-      children: value == groupValue ? [new Container(style: _dotStyle )] : []
+  Node buildContent() {
+    return new EventTarget(
+      new Material(
+        style: highlight ? _highlightStyle : _style,
+        children: value == groupValue ? [new Container(style: _dotStyle )] : []
+      ),
+      onGestureTap: _handleClick
     );
   }
 
   void _handleClick(_) {
     onChanged(value);
   }
 }