Readme: add project logo (#1425)

Add Beautiful QUnit Logo!!

* Update README.md

* Add files via upload

* Update README.md

* Update README.md

* Update README.md

Author: JimLynchCodes

README.md

@@ -1,3 +1,5 @@
+<img src="/docs/img/QUnit-Logo-Large.png" width="250" height="auto">
+
 [![Build Status](https://travis-ci.com/qunitjs/qunit.svg?branch=master)](https://travis-ci.com/qunitjs/qunit)
 [![Coverage Status](https://coveralls.io/repos/qunitjs/qunit/badge.svg)](https://coveralls.io/github/qunitjs/qunit)
 [![Chat on Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/qunitjs/qunit?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)