Encoding API sample

Data files and code for the the Encoding API sample.

@devnook and any other interested parties, please take a look if you have a minute.

Live demo at https://rawgit.com/jeffposnick/samples/encoding-api/encoding-api/index.html, though the CORS headers on that host are set up to prevent fetching the data files, so it's not a great demo. It works when served from GitHub Pages.