Optimizing Canvas/Tilemap when scale or color are set on Flash

Currently, when scale or color are set on a Canvas (or Tilemap), rendering is done with BitmapData.draw using a transformation matrix and tint, instead of the much faster copyPixels. This results in a significant performance hit each frame. With this update, the scaled/colored images will be drawn only once onto intermediate buffers, then these will be drawn to the screen using copyPixels each frame, resulting in much faster rendering.