Hi all, I have a 2013 13" MBA that I'd like to keep awake when plugged in and open. At the moment it goes to sleep after a period of inactivity and there seems to be no way to stop this. Obviously this is fine when on battery, but when I have my laptop connected to power and an external screen, I'd it to remain awake even after the display turns off so I can remain connected to Skype and IRC. If I want it to sleep, I'll put it to sleep myself. At the moment I use Caffeine to keep it awake, but I'd still like the screen to go to sleep. My MacBook Pro running 10.8 has a slider for this but my MBA running 10.9 does not. Anyway to get this working?