message: Atlas: don't force move semantics on metadata insert
diff: @@ -226,7 +226,7 @@ class TextureAtlas {
  unsigned _format,
  Buffer _data,
  unsigned _user,
  - Metadata&& _metadata = {})
  + Metadata _metadata = {})
  {
  // fail early if to-be-inserted texture is too large to fit a single page in the whole atlas
  if (_height > height_ || _width > width_)
  