display build status for only master branch

Author: rburns

README.md

@@ -1,6 +1,6 @@
 ## Ansi to Html
 
-[![](https://img.shields.io/travis/rburns/ansi-to-html.svg)](https://travis-ci.org/rburns/ansi-to-html/branches)
+[![](https://travis-ci.org/rburns/ansi-to-html.svg?branch=master)](https://travis-ci.org/rburns/ansi-to-html/branches)
 [![](https://img.shields.io/npm/v/ansi-to-html.svg)](https://www.npmjs.com/package/ansi-to-html)
 ![](https://img.shields.io/npm/dm/ansi-to-html.svg)