Restore the previous and next links to their former glory.

Squashed commit of the following:

commit 6e788887da9dc91c6deb0e7fc81526592c0f60a5
Author: Adam Harvey <aharvey@php.net>
Date:   Wed Nov 20 11:47:11 2013 -0800

    Move the prevnext-container into the breadcrumbs.

commit d58a00dfbf61e7ff57cd350a64c57ab066141d81
Author: Adam Harvey <aharvey@php.net>
Date:   Wed Nov 20 11:40:09 2013 -0800

    OK, this is minimally functional.

commit 5b4c2e30a27d658d9b5bce4278823277554a2835
Author: Adam Harvey <aharvey@php.net>
Date:   Wed Nov 20 11:38:40 2013 -0800

    Various fixups.

commit 8bb763d18ac8c0d47094b1681e5acab8b6365b66
Author: Adam Harvey <aharvey@php.net>
Date:   Wed Nov 20 11:26:25 2013 -0800

    Revert "Kill the next/prev page from the top & move lang chooser"

    This reverts commit f613c040783ce882cc3c008e9f5fdf3cb6306037.

    Conflicts:
    	include/header.inc
    	include/shared-manual.inc
    	styles/theme.css