Rework libp2p-identify (#116)

* Add a proper PeerId to Peerstore

* Turn identify into a transport layer

* Expose the dialed multiaddress

* Add identified nodes to the peerstore

* Allow configuring the TTL of the addresses

* Split identify in two modules

* Some comments and tweaks

* Run rustfmt

* Add test and bugfix

* Fix wrong address reported when dialing

* Fix websocket browser code

* Support the p2p protocol in libp2p-identify

* Fix concerns

* Fix libp2p-dns

* More concerns

example/examples/ping-client.rs

@@ -83,7 +83,7 @@ fn main() {
     let (tx, rx) = oneshot::channel();
     swarm_controller
         .dial_custom_handler(target_addr.parse().expect("invalid multiaddr"), ping::Ping,
-            |(mut pinger, future)| {
+            |(mut pinger, future), _| {
                 let ping = pinger.ping().map_err(|_| unreachable!()).inspect(|_| {
                     println!("Received pong from the remote");
                     let _ = tx.send(());