ICE kinematics

Sticking an ICE tree on a mesh and then getting the, updating it, and setting the doesn’t really work. And I’m not sure it should. Between ICE optimizations and the way the XSI evaluation model works, I don’t think you’ll get consistent updates. SCOPs are similar, but they have that Always Evaluate flag to force evaluations.

Second attempt. I also have an ICE Tree in the Modeling region that initializes self.tmp.