AnimatedImages should be cached and shared internally

Image item in QML is stored in the pixmap cache which means that if several Image elements have the same source, only one copy of the image will be loaded.
This is not the case with the AnimatedImage item. The animated images not being shared is a limitation in QML. Say you want to make a little RTS or whatever game with a hundred characters, each having four animations a 32 frames at a 64x64 resolution. This starts to use alot of memory, so it would be good if the AnimatedImage would use a cache as well.