[Renderer][Suggestion] Reflective categories

[di57inct]

It would be nice to be able to select what to render in the following categories:

1. Map entities(brush/studio/sprites) - since it looks bad when not having the entire map rendered in reflections and usually there aren't many anyway so it wouldn't be such a big performance killer
2. Player(entities 1 -> MaxPlayers) models + sprites(radio message/weapon muzzle flashes)
3. Third party studio models(others than map entities and players)
4. Sprites(I don't think sprites have such a big impact on performance so there's probably no need to disable them or to have a 3rd party option though)

Thank you very much for this outstanding project :)