Add support for swiping left/right to close/open mobile nav.

Adds a custom build of jQuery mobile that ONLY includes the necessary
modules for swipe events.
Prevent content scrolling in mobile browsers when nav open.
Merge pull request #580 from kabel/swipe-nav

Swipe open/close mobile navigation
Clarify less breakpoint description
Merge pull request #582 from skoolbus39/develop

Clarify less breakpoint description, test pull request from Ryan
Merge remote-tracking branch 'upstream/develop' into develop