message: gltfpack: Extend needsDummyBuffers to cover images
  Previously gltfpack could crash when reading image data from a buffer
  view that didn't have a valid buffer associated with it.
diff: @@ -298,6 +298,14 @@ static bool needsDummyBuffers(cgltf_data* data)
  }
  }
  + for (size_t i = 0; i < data->images_count; ++i)
  + {
  + cgltf_image* image = &data->images[i];
  +
  + if (image->buffer_view && image->buffer_view->buffer->data == NULL)
  + return true;
  + }
  +
  return false;
  }
  