docs(README): remove TravisCI build status badge

Closes: #147

Author: staltz

README.md

@@ -18,7 +18,6 @@ __  _____| |_ _ __ ___  __ _ _ __ ___
 
 ![](https://badge-size.herokuapp.com/staltz/xstream/master/dist/xstream.js.svg)
 ![](https://badge-size.herokuapp.com/staltz/xstream/master/dist/xstream.min.js.svg?compression=gzip)
-[![Build Status](https://travis-ci.org/staltz/xstream.svg?branch=master)](https://travis-ci.org/staltz/xstream)
 [![ComVer](https://img.shields.io/badge/ComVer-compliant-brightgreen.svg)](https://github.com/staltz/comver)
 [![Gitter](https://img.shields.io/gitter/room/nwjs/nw.js.svg?maxAge=2592000)](https://gitter.im/staltz/xstream)
 

markdown/header.md

@@ -9,7 +9,6 @@
 
 ![](https://badge-size.herokuapp.com/staltz/xstream/master/dist/xstream.js.svg)
 ![](https://badge-size.herokuapp.com/staltz/xstream/master/dist/xstream.min.js.svg?compression=gzip)
-[![Build Status](https://travis-ci.org/staltz/xstream.svg?branch=master)](https://travis-ci.org/staltz/xstream)
 [![ComVer](https://img.shields.io/badge/ComVer-compliant-brightgreen.svg)](https://github.com/staltz/comver)
 [![Gitter](https://img.shields.io/gitter/room/nwjs/nw.js.svg?maxAge=2592000)](https://gitter.im/staltz/xstream)