Scene is a group(list) of paints.
This class is designed for vector data set which is prepared before canvas.
If a set of vector data is loaded from other resources such as files,
they can construct these data set using Scene.
This then can be pushed into canvas as one completed image.
Scene is supposed to be used in svg loading and storing to tvg specific data format(tvg)
Change-Id: Ie2ffebf74e79c59d99a77880630a54b6baad7eec
PaintNode -> Paint
ShapeNode -> Shape
SceneNode -> Scene
We can keep clean and neat shorter names.
Change-Id: Ic8521d456d947985e5fbe1ba2bde06faa1f52469
