Add option to close TCP connection after message

examples/irccat.json

 {
-  "tcp_listen": ":12345",
+  "tcp": {
+    "listen": ":12345",
+    "close_after_message": false
+  },
   "http": {
     "listen": ":8045",
     "tls": false,

tcplistener/tcplistener.go

 	var err error
 
 	listener := TCPListener{}
-	listener.socket, err = net.Listen("tcp", viper.GetString("tcp_listen"))
+	listener.socket, err = net.Listen("tcp", viper.GetString("tcp.listen"))
 	if err != nil {
 		return nil, err
 	}
 			log.Infof("[%s] message: %s", conn.RemoteAddr(), msg)
 			l.parseMessage(msg)
 		}
+		if viper.GetBool("tcp.close_after_message") {
+			conn.Close()
+		}
 	}
 }