Envmap not removed when loading a scene without one
When using a scene with an envmap (e.g. table_lucy_envmap.msf), if another one without an envmap is loaded (e.g. material_export.msf"), the envmap is not removed.
When using a scene with an envmap (e.g. table_lucy_envmap.msf), if another one without an envmap is loaded (e.g. material_export.msf"), the envmap is not removed.