Make gettext usable for Ocaml >= 4.2
New Slacko release

Added `users.info` binding, broken up huge monolithic type info smaller,
more relevant types per function. Still iterating on API design.
Merge pull request #2826 from tobiasBora/master

Make gettext usable with Ocaml >= 4.2
Merge pull request #2828 from Leonidas-from-XIV/feature/slacko.0.9.1

New Slacko release