Proposed clean up on subject text

To wrap up that thread on describing the two options for Subject content
(the one Rob, Ron, Conor, me, etc. presented text for), here's a small
modification to Rob's text that adds Ron's clarification:

"A <Subject> element can contain both an identifier and zero or more subject
confirmations which a relying party can verify when processing an assertion.
Once any subject confirmations are verified, the relying party can treat the
entity presenting the assertion as the entity that the SAML authority
associates with the name identifier and the claims in the assertion.

Alternatively, a <Subject> element can contain one or more subject
confirmations without an identifier being present. In this case, once any of
the subject confirmations are verified, the relying party can treat the
entity presenting the assertion as the entity that the SAML authority
associates with the claims in the assertion."

The intent, of course, is that "can treat the entity presenting the
assertion as...." is code for "it means whatever you want it to mean".

-- Scott