Merge pull request #3314 from ey6es/metavoxels

Support for scaling splat textures in S and T, use mipmaps for them.
fix for clearJointData() in JS scripts

let the JointState class verify animation priority
Merge pull request #3315 from AndrewMeadows/inertia

quick fix for clearJointData() in JS scripts
Merge branch 'master' of https://github.com/highfidelity/hifi into metavoxels