Replaces animator with a simpler system that can overlay multiple
animations
Character animation split into two layers, motion and action.
Walking, running and jumping animations are played on the first
layer, actions such as firing can be overlayed on the second.
More work is needed to limit overlap to only the weapons that make
sense.
Move frame transform data into Skeleton instead of Animator.
Animator now responsible for mutating Skeleton state.
Skeleton is more flexible for things like vehicle skeletons.
Animators now store Frame keyframes more sensibly
Animators can interpolate between two keyframes on an alpha
Add tick alpha value to the rendering pipeline