fix(readme): make the server example compile.

README.md

@@ -25,15 +25,12 @@ in non-backwards-compatible ways without warning.__
 Hello World Server:
 
 ```rust
-fn hello(mut incoming: Incoming) {
-    for conn in incoming {
-        let (_, mut res) = conn.open().unwrap();
+fn hello(_: Request, res: Response<Fresh>) {
     *res.status_mut() = status::Ok;
     let mut res = res.start().unwrap();
     res.write(b"Hello World!");
     res.end().unwrap();
 }
-}
 
 fn main() {
     let server = Server::http(Ipv4Addr(127, 0, 0, 1), 1337);