Clean up examples directory

sky/examples/stocks/lib/stock_menu.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 'package:sky/framework/components/popup_menu.dart';
 import 'package:sky/framework/fn.dart';
 import 'package:sky/framework/theme/view-configuration.dart';
 
 class StockMenu extends Component {
   static final Style _style = new Style('''
@@ skipping 12 matching lines @@
         items: [
           [new Text('Add stock')],
           [new Text('Remove stock')],
           [new Text('Help & feeback')],
         ],
         level: 4),
         _style
     );
   }
 }