PR. #311

I just created the PR #311:
"Data model chapter updated in CORE doc. Message structure for supported
protocols updated in TRANSPORT doc."

The chapter was updated with the view in mind that it is better to
reference to the original (i.e. the VSS github site) than to duplicate
information (which then needs update if the original changes).

I think the Data model chapter is the right place to bring up the issues of
Service discovery and Registry. Related to the latter I took the liberty of
introducing (a teaser on) my view on how dynamic service registration
should be designed, through an API separate from the "main" Vehicle API we
are defining.
I would be glad to present my complete ideas on that in a coming WG
meeting.

BR
Ulf