Add badges to README.md

Author: lttb

README.md

@@ -1,5 +1,10 @@
 # Styled Components on top of JSS
 
+[![Travis branch](https://img.shields.io/travis/cssinjs/styled-jss/master.svg?style=flat)](https://travis-ci.org/cssinjs/styled-jss)
+[![Coverage Status branch](https://img.shields.io/coveralls/cssinjs/styled-jss/master.svg?style=flat)](https://img.shields.io/coveralls/cssinjs/styled-jss/master.svg?branch=master)
+[![npm version](https://img.shields.io/npm/v/styled-jss.svg?style=flat)](https://www.npmjs.com/package/styled-jss)
+[![npm license](https://img.shields.io/npm/l/styled-jss.svg?style=flat)](https://www.npmjs.com/package/styled-jss)
+
 ## Install
 
 This has peer dependencies of `react` and `react-dom`, which will have to be installed as well.