Revert "summ" to "list"; rename lists to groups

I just could not get my fingers to learn "bib summ ..." which I think was
indicative. I thought about calling groups "sets", but then "bib set ..."
would be taken up which could potentially get confusing.
bibtools/bibtex.py: include title for books by default
bibtools/bibtex.py: much more sensible OO styling approach
bibtools/bibtex.py: render Proc. SPIE as article for ApJ