Add travis.yml and badges.

and other buttons...

![alt text](https://img.shields.io/chrome-web-store/v/daiejhinmmfgincamkeeobmpffhdljim.svg)
![alt text](https://img.shields.io/chrome-web-store/d/daiejhinmmfgincamkeeobmpffhdljim.svg)
![alt text](https://img.shields.io/travis/backtickbacktick/backtick.svg)