message: gltfio ubershader mode: set sheen to OPAQUE.
  This makes ubershader mode more consistent with jit mode.
  SheenChair and ToyCar in the samples repo both have opaque cloth.
diff: @@ -2,7 +2,7 @@ material {
  name : sheen_${SHADINGMODEL}_${BLENDING},
  requires : [ uv0, uv1, color ],
  shadingModel : ${SHADINGMODEL},
  - blending : fade,
  + blending : opaque,
  depthWrite : true,
  doubleSided : ${DOUBLESIDED},
  transparency : ${TRANSPARENCY},
  