function removePipelineExtras(gltf) {
  ForEach.shader(gltf, function (shader) {
    removeExtras(shader);
  });
  ForEach.buffer(gltf, function (buffer) {
    removeExtras(buffer);
  });
  ForEach.image(gltf, function (image) {
    removeExtras(image);
  });

  removeExtras(gltf);

  return gltf;
}
Iterate through the objects within the glTF and delete their pipeline extras object.

@param {object} gltf A javascript object containing a glTF asset.
@returns {object} glTF with no pipeline extras.

@private