With ML's Airplay feature, is it possible to use it from one mac to another? I have an old Macbook (running Snow Leopard) hooked up to my TV for Plex. I am getting a new MBA (should arrive this week). Will I be able to mirror what I have on my Air while sitting on the couch, to my TV? I don't mind updating the old macbook that's hooked up to my TV to ML, if necessary, but is it possible to do this with a macbook, instead of appleTV?