[tm-pubsubj-comment] updated documents

I've hard time working with the psdoc proposal after last meeting. See new version at:
http://www.oasis-open.org/committees/tm-pubsubj/docs/recommendations/psdoc.htm

I've taken the option of getting rid at the moment of all the controversial stuff which is
in the issues document, that I have not updated yet. I've added a few things to what we
have discussed, mainly the notion of "Subject Sets", that is so obvious that we forgot to
mention it all along.

Comments as usual.

Bernard