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.

signature S = sig
        type t
        val x : t
end

signature S' = sig
        include S
        val y : t
end

signature S'' = sig
        type u
        include S' where type t = int
        type v
end