[MLton] the syntax of MLBs

[Henry Cejtin]

I really like the idea of file names being in quotes because the conventions
different people/OS's use (like spaces and newlines on Mac's) vary greatly.
I also kind of like the idea of include since then file boundaries are up
to the user (to some extent).
The use of open is kind of distasteful because open in its normal meaning is,
but that isn't a very strong argument.
Note, I agree that it is unfortunate if you MUST use multiple files (one mlb
and the rest sml at least) for simple programs.  This isn't because of
`scripting' (what ever that means exactly) but just in terms of syntactic
noise.