Suggested Edits for Version Control With Git

Hey @bilderbuchi, I got a chance to read over your chapter and suggest some edits. Only a few minor changes and suggestions here and there. You did a nice job covering a broad (and somewhat disconnected from the rest of the book) subject briefly but with great clarity. Here are a few thoughts that I left out:

- How to properly remove files. `git rm` and `git mv` instead of `rm` and `mv` (or via the GUI). Also what to do if the files have been deleted the wrong way (I use `git add -u` but there might be a better way).
- [Mention Git Color](http://git-scm.com/book/en/Customizing-Git-Git-Configuration#Colors-in-Git). It is wildly helpful!
- [Try Git](http://try.github.io/levels/1/challenges/1) is an __excellent__ interactive tutorial. I like it so much that it might even deserve a mention somewhere in the body of the chapter (at least a mention in the resources section if not).