[MLton] Further on Regressions

[Brent Fulgham]

1.  Date test is only failing because Win32 likes to
pad the day field with zeros (e.g., 1 -> 01).  This
fails the string-match.

I don't think this is worth working on at the moment.

2.  Most of the filesystem stuff works now.  I had
stubbed a few things out and forgotten about them. 
I've fixed that and it seems to work.

The main remaining thing is getting signals to work. 
I'm not sure how much effort this will be.

-Bren