[MLton] Windows structure

[Vesa Karvonen]

I have started implementing a Windows library for MLton.  You
can find it from the mltonlib repository at:

  http://mlton.org/cgi-bin/viewsvn.cgi/mltonlib/trunk/com/ssh/windows/unstable/

At the moment, the bindings are implemented using NLFFI and C
stubs.  Hopefully we can remove most of the C stubs in the
future when MLton's NLFFI understands calling convention
specifiers.  Some amount of string/buffer copying is being
made that could be eliminated using MLton's lower level FFI.
I'm not in any hurry to do so, however.

The Windows structure doesn't yet implement all of the Basis
Library spec.  If you need some Windows functionality, feel
free to submit patches.  I'll probably only add new stuff to
the Windows library when I specifically need it.

-Vesa Karvonen