libstd: "import" -> "use"

src/libstd/net.rs

@@ -1,10 +1,10 @@
 //! Top-level module for network-related functionality
 
-import tcp = net_tcp;
+use tcp = net_tcp;
 export tcp;
 
-import ip = net_ip;
+use ip = net_ip;
 export ip;
 
-import url = net_url;
+use url = net_url;
 export url;