Upgrade to jQuery 2.2.2 and RequireJS 2.2

Release notes:

• http://blog.jquery.com/2016/03/17/jquery-1-12-2-and-2-2-2-released/
• http://requirejs.org/docs/download.html#2-2-0

Regarding the jQuery upgrade, the move from 1.x to 2.x is justified because:

jQuery 2.x has the same API as jQuery 1.x, but does not support Internet Explorer 6, 7, or 8.

and we don't support IE9 or older as specified in our Browser Support Strategy.