Generate deterministic column ordering in insert and update queries
This patch was authored and released by @gwynne.
This is an updated version of #556 by @rausnitz which updates the generation of INSERT
queries to be both deterministic and more performant by eliding pointless repetition of the Fluent -> SQL conversion of the field list.
Additional kudos for @rausnitz for his enthusiasm, which inspired me to take another hard look at the existing logic!
Closes #543