anchor.diff:  /// ## Class BoneAnimation
   /// represents Key frame animation data for a single bone in a skeleton.
   class BoneAnimation {
  -  final int boneIndex;
  +  final Bone bone;
   
     List<double> _positionTimes;
     List<VM.Vector3> _positionValues;
  
positive.code:     VM.Quaternion r = _rotationValues[rotationIndex];
      boneMatrix.setFromTranslationRotationScale(t, r, s);
    }
  }
  
  /// ## Class SkeletalAnimation
  
negative.code:       : animList = new List<BoneAnimation>(length);
  
    void InsertBone(BoneAnimation ba) {
      assert(animList[ba.bone.boneIndex] == null);
      animList[ba.bone.boneIndex] = ba;
    }
  }
  
  