Auto-IK: applying back the IK transform on bones fails for constrainted bones themselves. This would require the post-transform of IK to be converted to a pre-transform for the constraint. That's too much of a headache for bugfixing days. To keep the autoIK feature work it now stops IK chains at constrainted bones. Added todo item for a matrix wizzard to fix this one day. (What would be really cool is a matrix-api for armature to easily get all the required pre- and post transforms and apply. There's a lot of duplicate exception handling for hinge bones for example.)