DevGuide trunk - merged through chapter 8

Looks fantastic, guys! Thanks for your continue hard work on this.

It contains changes through chapter 8 from Russ' branch. It also has a small amount of your changes for chapters 9 and 10. I'll get the rest of your changes to these chapters after Rich has finished review of them.

Note, I had to make a handful of changes in order to get some of the images to display and to preserve step numbering. I'll insert comments in the commits here on Github.

Thanks again!

@sez11a, @rbohl