Update Git Cheat Sheet with Setup/Init corrections

Thanks to @dice for observing some inconsistencies in the "Setup" and "Init" sections.

### Updated
![screen shot 2014-03-12 at 11 54 50 am](https://f.cloud.github.com/assets/352082/2400868/6c7b7b94-aa0f-11e3-8836-0c50d70d1710.png)