[MLton] mlb files and the ML Kit

[Matthew Fluet]

Martin,

You provided a lot of helpful input when we discussed mlb files back in
March.  I was wondering if you had a chance to look at their realization
in the latest MLton experimental release and whether you had any further
thoughts on coordinating efforts towards a common format for MLton and the
MLKit.  I noticed that the MLKit had a silent 4.1.4 release with some
preliminary pickling of compiler bases.