pub fn play() {
    let mut game = Game::new();

    loop {
        match game.turn() {
            Ok(()) => { game.turn += 1 }
            Err(e) => println!("{}", e)
        }
    }
}

fn foo() -> Result<(), Box<Error>> {
    try!(std::fs::File::open("not-here")); // io::Error
    try!(Err("oh noooo!"));   // &str
    try!(Err("I broke it :<".to_owned()));  // String
    Err("nop".into())
}