Switch to using Zurb gem and clean up email form
Instead of linking from a cdn we're including the zurb gem.
Since I'm going to use cloudflare I'd rather have one minified js and
css asset served if I can.

Added binstubs to git. I don't totally understand the new binstub
system. I should see if I can track something down explaining the 3.X ->
4.0 transition there.

Fixed email sign up so it looks a little nicer.