Lab tuneup

Tuning up the labs I indicated I would in https://github.com/github/training-team/issues/1044#issuecomment-57476960

@jordanmccullough and @brntbeer would you give these a quick look and :+1: shipping them?  They are pretty un-controversial and just add detail to the lab steps
The [GitHub Flow Guide](https://guides.github.com/introduction/flow/)? :+1: