Sort downloaded categories + hardware button support

[elan]

@Sytzeschalk

Add support for hardware buttons. This might be a niche use scenario, I know, but at least on the Hiby, all major streaming and music apps already support the players’ hardware buttons

Interesting, what hardware buttons are these? If nothing else, try mashing on them and then send over Plexamp logs, it might show what buttons we’re currently ignoring.