Add DTD and CSS from original drop.

[mike.kup...@sun.com]

Author: Mike Kupfer <Mike.Kupfer at Sun.COM>
Repository: /hg/onnv/devref
Latest revision: be02d2cd56396ec47542ecbdcb74bcbf2976fb5b
Total changesets: 1
Log message:
Add DTD and CSS from original drop.
The DTD is needed for "make check".
The CSS provides the opensolaris.org style.

Files:
        create: docbookx.dtd
        create: format.css