extension UserDefaults {
    @objc dynamic var user: Int {
        return integer(forKey: "user")
    }
    @objc dynamic var expansionPrefix: String? {
        return string(forKey: "prefix")
    }
}
static var onUserChange = UserDefaults.standard.observe(\.user, options: [.initial, .new], changeHandler: { (defaults, change) in
    func listenForEvents() {
        if change.isPrior {
            setMenu(state: .Loading)
            setMenu(state: .MainMenu)
        } else {
            setMenu(state: .Setup)
        }
    }
})