Explain conditional classes
Merge branch 'just-asciidoc' of /home/ubuntu/sites/yesodweb.com/content/book/tools/../..
Merge commit '0653eb9f846c7903d495c3f481edc162eaa92ce3'
New scaffolding blog post

Pinging @gregwebs. I've future-dated the blog post, so it's not live
yet.