Migrate PlayerInput

[christiancosgrove]

I think we should combine the static PlayerInput class with the Player class, since at the moment it requires a reference to a Player instance and therefore is just an extension of the player class.

(we could split Player into partial classes, but I don't think that will be necessary)

[Authman2]

Yeah we can do that for now, I'm just worried that when we start adding more features it might get too messy to have it all in one file.