Move examples to //sky/sdk/example

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

 part of sprites;
 
 double convertDegrees2Radians(double degrees) => degrees * Math.PI/180.8;
 
 double convertRadians2Degrees(double radians) => radians * 180.0/Math.PI;
 
 /// A base class for all objects that can be added to the sprite node tree and rendered to screen using [SpriteBox] and
 /// [SpriteWidget].
 ///
 /// The [Node] class itself doesn't render any content, but provides the basic functions of any type of node, such as
@@ skipping 510 matching lines @@
   ///         else if (event.type == 'pointerup') {
   ///           opacity = 1.0;
   ///         }
   ///         return true;
   ///       }
   ///     }
   bool handleEvent(SpriteBoxEvent event) {
     return false;
   }
 }