Files for DocBook

Hi Norm, hi everyone,

One of my action items for this week was to look at how ITS could be integrated with DocBook.

This is a first attempt to that. The zip file includes:
- DocBook.html: some explanations
- *.xsd: the XML Schema files needed for validation
- *.xml: some DocBook document example.

I've worked only on DocBook v5 and XSD schema, but there are more versions of DocBook and it can also use DTD as well as RELAX NG
schemas, so more may be needed if we want to cover most of docBook cases.

Norm:

I have not looked at all the DocBook elements to see of additional ITS data categories could be mapped (for example maybe DocBook
has an equivalemnt for Ruby or localization notes). I'm also not sure about the element that are usually translated vs. the ones
that are not, hopefully the ones listed in the HTML file are correct.

I would appreciate a lot if you could find a few minutes to look at this first attempt and point me to any mistake I would have
made.


Cheers,
-yves