Move examples to //sky/sdk/example

sky/sdk/example/rendering/touch_demo.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 'dart:sky' as sky;
 
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/paragraph.dart';
 import 'package:sky/rendering/sky_binding.dart';
@@ skipping 70 matching lines @@
   var stack = new RenderStack(children: [
     new RenderTouchDemo(),
     paragraph,
   ]);
   // Prevent the RenderParagraph from filling the whole screen so
   // that it doesn't eat events.
   paragraph.parentData..top = 40.0
                       ..left = 20.0;
   new SkyBinding(root: stack);
 }