Mobile-friendly breadcrumbs

Foundation includes a breadcrumbs component. However, it lists breadcrumbs horizontally which isn't very mobile-friendly.

Foundation Mobile includes a mobile-friendly breadcrumb component styled like a secondary navbar, which is much easier to use on touch devices.

The mobile breadcrumb bar at the top also uses the truncate component for the name of the current page. Since it's used only as an non-critical indicator of the page the person is on, it doesn't need to expand when clicked, so we left out the data-truncate attribute.