improve localnet-sanity's robustness (#1160)

* fix poll_gossip_for_leader() loop to actually wait
         for 30 seconds
    * reduce reuseaddr use to only when necessary,
         try to avoid already bound sockets
    * move nat.rs to netutil.rs
    * add gossip tracing to thin_client and bench-tps

src/lib.rs

@@ -30,8 +30,8 @@ pub mod ledger;
 pub mod logger;
 pub mod metrics;
 pub mod mint;
-pub mod nat;
 pub mod ncp;
+pub mod netutil;
 pub mod packet;
 pub mod payment_plan;
 pub mod record_stage;
@@ -72,6 +72,7 @@ extern crate jsonrpc_http_server;
 extern crate log;
 extern crate nix;
 extern crate rayon;
+extern crate reqwest;
 extern crate ring;
 extern crate serde;
 #[macro_use]