GSoC / JENA-491 / "Extend CONSTRUCT to build quads"

[Andy Seaborne]

I'd like to merge this into master having done what testing I can.
If that's OK, then I'll go ahead.

There will be a massive number of commit emails on commits@jena because 
it repeats merged branches and this goes back several months, unless it 
truncates the deluge.

        Andy