add Travis badge

Author: celeduc

README.md

@@ -1,5 +1,6 @@
 # java-multihash
 
+[![Build Status](https://travis-ci.org/multiformats/java-multihash.svg?branch=master)](https://travis-ci.org/multiformats/java-multihash)
 [![](https://img.shields.io/badge/made%20by-Protocol%20Labs-blue.svg?style=flat-square)](http://ipn.io)
 [![](https://img.shields.io/badge/project-multiformats-blue.svg?style=flat-square)](http://github.com/multiformats/multiformats)
 [![](https://img.shields.io/badge/freenode-%23ipfs-blue.svg?style=flat-square)](http://webchat.freenode.net/?channels=%23ipfs)