[away3d] collada override or blend bone parameters

[kensuguro]

I got a collada with keyed bones, and I want to grab one and change
its rotation at runtime.  But instead of just overriding, I would
preferably blend the paramter..  is it possible to change the
paramters post transformation from keyframes but pre render?  for ex,
if the keyframe's rotationY is at 30, then I'd want that to be
applied, so I can use the value to calculate what the final rotation
should be, apply it, and then render it.  I'm doing a character with a
free looking head.