[Tweener] Color filters not compatible.

[Bradley]

I'm trying to tween _brightness and _contrast with one tween like so:

Tweener.addTween(someClip, {_brightness:-.5, contrast:.5, time:.5};

It seems like the two props can't be used with each other, and the  
second one defined overwrites the first.

Tweener.addTween(someClip, {_brightness:-.5, contrast:0, time:.5};

should yield the same result as

Tweener.addTween(someClip, {_brightness:-.5, time:.5};

but the first one does nothing at all. The second one actually  
changes the brightness like both of them should.