Upgrade jQuery Rails from 4.0.5 to 4.1.1

Upgrades jQuery to 1.12.1 and jquery-ujs to 1.2.1.

Changelogs:

• https://github.com/rails/jquery-rails/blob/master/CHANGELOG.md
• https://blog.jquery.com/2016/01/08/jquery-2-2-and-1-12-released/
• https://github.com/rails/jquery-ujs/releases

cc: @rspeicher