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
The folder `gh_pages/lib` is gitignored since it's part of `gh_pages`. Good point about `app/app.coffee`. I'm not sure why that worked.