s&box: Driving character animations with SkinnedModelRenderer — Set parameters, IK, bone transforms, events

In s&box, animating skinned models (characters, creatures) requires setting parameters on SkinnedModelRenderer via Set() or the Parameters accessor. Developers coming from Unity try to use Animator.SetFloat/SetBool but the API is different. Also, IK targets, look direction, and animation events all have specific patterns.