change format! to concat() and modify listen() to take &String instead of String

src/game/new.rs

@@ -36,8 +36,8 @@ impl Game {
 			tokens.push_back(Token(i));
 		}
 
-		let server_address = format!("{}:{}", config.server.ip, config.server.port);
+		let server_address = [&config.server.ip, ":", &config.server.port.to_string()].concat();
-		let mut server = Server::listen(server_address.clone(), Token(0))?;
+		let mut server = Server::listen(&server_address, Token(0))?;
 		info!("Listening on {}", &server_address);
 
 		let poll = try_log!(Poll::new(), "Unable to create Poll");

src/server.rs

@@ -27,7 +27,7 @@ pub struct Server {
 
 impl Server {
 	/// Bind to the provided address
-	pub fn listen<'a>(addr: String, token: Token) -> RudeResult<Server> {
+	pub fn listen<'a>(addr: &String, token: Token) -> RudeResult<Server> {
 		let addr: SocketAddr = try_log!(addr.parse(), "Unable to parse server address: {}", &addr);
 
 		let socket: TcpListener = try_log!(