Blender Git Loki

Fix problem with limit rotation constraints during transform. This code
would convert from quat to matrix and back if the bone had any constraint,
but did not normalize the quat first as done in other places, giving a
sudden jump when starting transform on some bones with constraints. Two
changes:

* Normalize quaternion first.
* Only do this conversion on bones with limit rotation constraints,
instead of all bones with any constraint.