[RDFa] ISSUE-8: RDF containers in RDFa

Hi all,

There's one syntax issue we haven't talked about n a while that we
should probably address in *some* form: how to express RDF containers
and/or lists. In particular, how do we indicate a list of creators, or a
list of licenses, or a list of authors in a paper.

I wrote a proposal on RDFa containers a while ago:
http://www.w3.org/2001/sw/BestPractices/HTML/2006-rdfa-containers

but that assumed we would do RDF Bags and Sequences. I don't know yet if
that's what we should support, or if we should just focus on lists,
denoted [a,b,c] in Turtle.

Input from anyone, in particular the SWD WG, would be very helpful! I
think for XHTML1.1+RDFa, we should do the simplest thing that doesn't
completely prevent us from encoding lists of some kind.

In terms of implementation, the right direction is likely something
using UL, OL, and LI, possibly involving @href/@resource on the LI, as
we had expected @href everywhere in the original XHTML2-based proposal.

-Ben