[away3d] Render MovieClipSprite when its center is outside the screen

[Rujia Liu]

Hi everyone!

When using MovieClipSprite, I noticed that if the center (or other points,
according to the align mode) is outside screen, the whole MovieClipSprite is
not drawn. I'm using FrustumClipping + CORRECT_Z_ORDER renderer.

Is there a convenient way to prevent this? Thanks!

- Rujia