chore(readme): added code climate badge, fixed broken gitter badge

README.md

@@ -7,7 +7,7 @@
 [![Greenkeeper badge](https://badges.greenkeeper.io/opensheetmusicdisplay/opensheetmusicdisplay.svg)](https://greenkeeper.io/)
 [![Build Status](https://travis-ci.org/opensheetmusicdisplay/opensheetmusicdisplay.svg?branch=master)](https://travis-ci.org/opensheetmusicdisplay/opensheetmusicdisplay)
 [![Dependency Status](https://david-dm.org/opensheetmusicdisplay/opensheetmusicdisplay.png)](https://david-dm.org/opensheetmusicdisplay/opensheetmusicdisplay)
-[![Gitter](https://badges.gitter.im/Join Chat.svg)](https://gitter.im/opensheetmusicdisplay/opensheetmusicdisplay?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/opensheetmusicdisplay/opensheetmusicdisplay?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Code Climate](https://codeclimate.com/github/opensheetmusicdisplay/opensheetmusicdisplay/badges/gpa.svg)](https://codeclimate.com/github/opensheetmusicdisplay/opensheetmusicdisplay)
 
 Display sheet music ([MusicXML](http://www.musicxml.com) files) in the browser.