Move examples to //sky/sdk/example

sky/sdk/example/raw/spinning_arabic.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:math" as math;
 import 'dart:sky';
 
 double timeBase = null;
 LayoutRoot layoutRoot = new LayoutRoot();
 
@@ skipping 28 matching lines @@
   block.style['direction'] = 'rtl';
   block.style['unicode-bidi'] = 'plaintext';
   block.appendChild(arabic);
   block.appendChild(more);
 
   layoutRoot.rootElement = block;
 
   view.setBeginFrameCallback(beginFrame);
   view.scheduleFrame();
 }