GIT support

[fedetango]

There are libraries that allow you to use git completely from the browser. This is the case for "isomorphic-git".

It would be great to work with my GIT repositories (not GitHub) from the application.

I'd be happy if at first you could at least open a Git project without the need to be GitHub.

[abose]

Tracked as part of #145
Will be working on it post live preview and extension store.