update README

README.md

@@ -11,7 +11,7 @@ It is a port of [shadowsocks](https://github.com/shadowsocks/shadowsocks)
 created by [@clowwindy](https://github.com/clowwindy) maintained by 
 [@madeye](https://github.com/madeye) and [@linusyang](https://github.com/linusyang).
 
-Current version: 1.6.4 | [![Build Status](https://travis-ci.org/shadowsocks/shadowsocks-libev.png?branch=master)](https://travis-ci.org/shadowsocks/shadowsocks-libev) | [Changelog](Changes)
+Current version: 2.0.1 | [![Build Status](https://travis-ci.org/shadowsocks/shadowsocks-libev.png?branch=master)](https://travis-ci.org/shadowsocks/shadowsocks-libev) | [Changelog](Changes)
 
 Features
 --------
@@ -232,6 +232,8 @@ usage:
                                      not available in redir mode
           [-L <addr>:<port>]         setup a local port forwarding tunnel,
                                      only available in tunnel mode
+          [-d <addr>]                setup the name servers for libudns,
+                                     only available in server mode
           [-v]                       verbose mode