new version of usage

The new version is available from:
http://dev.w3.org/cvsweb/~checkout~/2002/ws/arch/scenarios/ws-arch-scenarios
.html

Changes:

1. Added Yin-Leng's management discovery scenario;
2. A large number of corrections to typos including those found by Yin-Leng;
3. Added additional scenario citations to the EDI case;
4. Corrected and added cross links among scenarios.


One of the requirements is to validate the architecture against use cases so
I'd like to invite everyone to do so.

Hao