Updated xml:lang proposal

Hi all,

Here's my latest xml:lang proposal. This one incorporates the 3 changes
discussed in yesterday's meeting. I added subsections to the Recommended
Usage section to make things clearer.

Best Regards,
Gershon

---
Gershon L Joseph
Member, OASIS DITA and DocBook Technical Committees
Director of Technology and Single Sourcing
Tech-Tav Documentation Ltd.
office: +972-8-974-1569
mobile: +972-57-314-1170
http://www.tech-tav.com