Tries to load jQuery over HTTP.

[mikelehen]

Mixed Content: The page at 'https://intro-to-firebase.firebaseapp.com/' was loaded over HTTPS, but requested an insecure script 'http://code.jquery.com/jquery-2.1.4.min.js'. This request has been blocked; the content must be served over HTTPS.

But it still works, so maybe jQuery isn't actually necessary and should just be removed?

[davideast]

Hmm must be a dependency of reveal.js. I'll make sure jQuery is brought down locally through Bower like Polymer.