Move examples to //sky/sdk/example

sky/sdk/example/game/lib/sprite.dart

 part of sprites;
 
 /// A Sprite is a [Node] that renders a bitmap image to the screen.
 class Sprite extends NodeWithSize {
 
   /// The texture that the sprite will render to screen.
   ///
   /// If the texture is null, the sprite will be rendered as a red square
   /// marking the bounds of the sprite.
   ///
@@ skipping 109 matching lines @@
         canvas.drawImageRect(texture.image, texture.frame, texture.spriteSourceSize, paint);
       }
     } else {
       // Paint a red square for missing texture
       canvas.drawRect(new Rect.fromLTRB(0.0, 0.0, size.width, size.height),
       new Paint()..color = const Color.fromARGB(255, 255, 0, 0));
     }
     canvas.restore();
   }
 }