Fetching posts from Facebook using JS SDK / Graph API. Crude demo of posting.

`posts.jsx`: Added loading state (`status`).

`index.html`: Added new `#container` for React to render into (was rendering into `body`).

`gulpfile.js`, `package.json`: Added moment.js library ( http://momentjs.com/ ). Calculates relative dates, e.g. "a few seconds ago", "2 months ago".