Feature/redirect to https

There's no way of configuring the ELB to redirect; it just terminates HTTPS there and forwards everything to port 80. So I tweaked the ELB listener to forward 80 -> 80 and 443 -> 443 (but HTTP, not HTTPS). That way, nginx can reply to anything coming in on 80 with a 301. ( @dlapiduz, take note.)
(In theory, it's possible to get nginx doing this with a single server listener since ELB sends the origin port details through, but this requires use of `if` which has [all kinds of nasties](http://wiki.nginx.org/IfIsEvil).)

To make the site happy on HTTPS, a few asset references needed changing. Placeholder images have been downloaded for the moment because [placehold.it](http://placehold.it) doesn't do HTTPS.
You can actually have the ELB re-encrypt the data and have SSL communication with your backend nginx server. I don't have strong feelings on whether this is necessary, but it might make your nginx configuration more portable (in other words, the ELB could be removed or swapped out with something else, and your instance could face the world directly with confidence and pride).