All my earlier test cases for software skinning had the polys parent transform to be identity. This works fine until you had cases where the user had moved the transform of the parent nodes of skinned polys.
This PR fixes this situation by taking into account the final (concatenated) transform of the polys RELATIVE to the skeleton base transform. It does this by applying the inverse skeleton base transform to the poly final transform.
(cherry picked from commit f33e22001f)