CAD11 — Documentation for CadMain::Model::unique_entities()

2. The Documentation for CadMain::Model::unique_entities() and CadMain::Model::top_level_entities() says the only valid types asked for are geometric entity types but there is only mention and used CadFoundation::Entity (in the doc and in the return types). If this should really be only geometric entities, the return types could be CadBrep::BrepEntity and the documentation should be much clearer on what is allowd and what a invalid type.