Cleans up interface (it's now a command line option) and renames project to "sqlcache" in the all-one-word style. Still has issues to do with concurrency, retrying transactions, and foreign function calls that either rely on state or have side effects.

type t = {A : int, B : float, C : string}
type u = {A : int, C : string, D : bool}

fun f (x : t) = x
fun g (x : u) = f x

fun h [ts] [ts ~ [A]] (r : $([A = int] ++ ts)) : $([A = int, B = float] ++ ts) = r