added version badge

Author: lgraubner

README.md

@@ -1,6 +1,6 @@
 # Node W3C Validator
 
-[![Build Status](https://travis-ci.org/lgraubner/node-w3c-validator.svg)](https://travis-ci.org/lgraubner/node-w3c-validator)
+[![Build Status](https://travis-ci.org/lgraubner/node-w3c-validator.svg)](https://travis-ci.org/lgraubner/node-w3c-validator) [![npm version](https://badge.fury.io/js/w3c-validator.svg)](https://www.npmjs.com/package/w3c-validator)
 
 Crawls a given site and checks for W3C validity.