[ietf-dkim] Issue 1571: Examples in SSP-03

[Stephen Farrell]

Issue description: https://rt.psg.com/Ticket/Display.html?id=1571

This calls for some sample encodings to be added to appendix A
of ADSP. No discussion ensued. It appears that ssp-04 doesn't
contain any samples as called for here.

I think this should remain open, but would encourage a quick
discussion so we can close it substantively, if not yet formally
(assuming we end up wanting some change/addition).

S.