message: gltfpack: Fix constant track detection for translations
  We were previously erroneously treating translation/scale tracks without
  changes in the first component as constant.
  Contributes to by fixing BoxAnimated.
diff: @@ -1393,7 +1393,7 @@ float getDelta(const Attr& l, const Attr& r, cgltf_animation_path_type type)
  {
  float error = 0;
  for (int k = 0; k < 4; ++k)
  - error += fabsf(r.f[0] - l.f[0]);
  + error += fabsf(r.f[k] - l.f[k]);
  return error;
  }
  