Animation updates

## Changes

`TimerManager` has been removed and each renderer will keep track of their own animations instead.

`RajawaliRenderer.addAnim(Animation3D)` has been added, similar to
`addChild(BaseObject3D)`, only for animations. Animations will be started
in `startRendering()`, paused in `stopRendering()`, and cancelled in
`destroyScene()`.

## To Do

* Update and test with [examples](https://github.com/MasDennis/RajawaliExamples)
* Figure out what to do (if anything) for `Rajawali[Fragment]Activity.onPause()`
* Figure out how this should work with `Animation3DQueue` objects
    * Common interface for `Animation3D` and `Animation3DQueue`?
        * start()
        * pause()
        * cancel()

## Example

Tested with the following renderer in the [wallpaper template](https://github.com/MasDennis/RajawaliWallpaperTemplate):
``` Java
public class Renderer extends RajawaliRenderer {

	public Renderer(Context context) {
		super(context);
	}

	public void initScene() {
		ALight light = new DirectionalLight();
		light.setPower(1);
		light.setPosition(0, 0, -5);
		mCamera.setPosition(0, 0, -7);
		mCamera.setLookAt(0, 0, 0);

		Cube cube = new Cube(1);
		DiffuseMaterial material = new DiffuseMaterial();
		cube.setMaterial(material);
		Bitmap texture = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.rajawali_tex);
		cube.addTexture(mTextureManager.addTexture(texture));
		cube.addLight(light);
		addChild(cube);

		Number3D axis = new Number3D(3, 1, 6);
		axis.normalize();
		Animation3D anim = new RotateAnimation3D(axis, 360);
		anim.setDuration(8000);
		anim.setRepeatCount(Animation3D.INFINITE);
		anim.setInterpolator(new AccelerateDecelerateInterpolator());
		anim.setTransformable3D(cube);
		addAnim(anim);
	}
}
```