message: fix shader dColorType_groupInstance texture read
diff: #elif defined(dColorType_group)
  vColor.rgb = readFromTexture(tColor, aGroup, uColorTexDim).rgb;
  #elif defined(dColorType_groupInstance)
  - vColor.rgb = readFromTexture(tColor, aGroup * float(uGroupCount) + aGroup, uColorTexDim).rgb;
  + vColor.rgb = readFromTexture(tColor, aInstance * float(uGroupCount) + aGroup, uColorTexDim).rgb;
  #elif defined(dColorType_objectPicking)
  vColor = encodeIdRGBA(float(uObjectId));
  #elif defined(dColorType_instancePicking)
  