C2MS12 — Documentation Changes to Move Away from Pub/Sub Expectation

C2MS has constructs and language that make it seem like a pub/sub specification, though that is merely one possible architecture. C2MS message define a format for messages that could be used in a service-based architecture.

To aid with this, we should not use the term 'publish', and we should be careful with 'subscribe'.

This is in order to get away from the assumption of a pub/sub architecture. This will include renaming the MEPS that have "Publish".

Note that some already-approved issues in this release might have used "Publish". Need to find and correct these.

We should further state that the Subject is optional used to aid message delivery, most useful in a pub/sub setup, but the subject is derived from, rather than adding to the message itself.

In the document, use terms like 'send' instead of 'publish'. Make the patterns refer to Notify rather than publish.