Initial preparations for automated deployment

The big thing here is deploy/README.md.

@afeld @konklone @gboone 
Bear in mind, Jekyll alone requires Ruby, Python, and Node right now. Ruby for Jekyll core, Python for pygments syntax highlighting (this could be moved to Rouge), and Node because Jekyll currently builds in CoffeeScript support and requires it (they've said they'll change this in the next version).

So we could get it down to just Ruby for Jekyll, and use Node only for the webhooks. The webhooks could also be dissociated from the repo more cleanly, and made their own package.