Add a confirmation before having the app close

[larsenv]

@V10lator Picture this. This just occurred. I was helping install a ton of games on a Wii U that is not mine, and my laptop was out. I start the process, and the charging cord of its GamePad gets tangled up with another cord charging my laptop. GamePad falls to the floor, and the download ends because NUSspli exits the app if you press home even if youre downloading stuff. In frustration because I was trying to exactly avoid this, I pound the GamePad with my charger. The actual screen breaks, and they have to buy a new one. Please prevent rage from occurring and add a way to confirm if you want to actually exit the app when you press home