update jquery.fullpage 2.1.8

I added jquery.easings.min.js 1.9.2; the repo author used jQuery.UI's build tool to make an [official reduced version](https://github.com/alvarotrigo/fullPage.js/tree/master/vendors).  By default, either `jquery.easings.min.js` or the full jquery.ui are needed.

I suggest future uploads include the repo's jquery.easings.min.js, unless he or someone else uploads this particular build elsewhere.