Add simple animation system

Add a simple animation system, and you can extend from MoveAnim to define a custom movement.

Add double buffer

I've added double buffer into FriceEngine, now it will refresh the scene in a fluent way.
Also some stdlib added, but a little buggy.

First release

you can add images into a frame, but it is refreshed five times a second(very slow), deciding to used BufferedImage to replace hard drawing by a graphics object.

wanna know how to used, please view root/demo/Demo1.java