Publish new gh-pages with every release

* Updates the gh_pages folder so it can stand alone
* Use release-it to push to gh-pages on every release

Other small tweaks:

* Use grunt-release-it as a wrapper for release-it
* Move bower dependencies to vendor/ folder

@dylnuge @bigsley @yayalice
Weird, so I guess we're bundling the bootstrap and d3 js code into our `app.js` - that sounds wrong. I'll see if I can fix it. Weirder, I'm not sure why we even have d3.