add regression tests for divide-by-zero

I've noticed a couple platforms / compiler combinations having problems
with properly handling divide-by-zero errors, so this patch updates the
regression tests to include this behaviour. I also took the liberty of
updating some Postquel terms their SQL equivalents (e.g. retrieve ->
select, etc.)

Cheers,

Neil
--
Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC