Refactoring Animated image visual

 - Animated image file will be opened when the visual is on scene.
 - Only the first frame is cached to cache single frame image as the image visual do.
 - Pause timer when next frame is not cached yet. And resume it after the frame is ready.
 - Load policy and release policy is now supported.

Change-Id: I39a1d93396865f56d6c7e0b54b9d9fffecdc88ef
Signed-off-by: seungho <sbsh.baek@samsung.com>