Null parameter checking, gitwrapper fix, and a comment fix

Hi,

Here is what I have been working on. If anyone is testing this on windows remember to hardcode the git executable in the gitcommands model, and also you need to generate an ssh key.

![works](https://f.cloud.github.com/assets/5598505/2427863/0420b726-ac12-11e3-8ae7-f257e8b278d3.PNG)

(Now let's hope it passes the travis build... :P )

@cdwainscott