Add JQuery

[KyNorthstar]

Since these scripts depend on JQuery, it's best to not assume that will be included elsewhere. Include them in this repo to help guarantee stability.

A script like this should be used:

var script = document.createElement('script');
script.src = '//code.jquery.com/jquery-3.x-git.slim.min.js';
script.type = 'text/javascript';
document.getElementsByTagName('head')[0].appendChild(script);

^{Adapted from a StackOverflow answer}