Protocol neutral references

Github pages use https instead of http. So including js and css from Google CDN via http fails in modern browsers.

<script src="//code.jquery.com/ui/1.10.4/jquery-ui.min.js"></script>
This snippet gets https://code.jquery.com/ui/1.10.4/jquery-ui.min.js on a https enabled site. On a http site  http://code.jquery.com/ui/1.10.4/jquery-ui.min.js is pulled.