new codegen

[Matthew Fluet]

> > The fix hopefully uses consistant column ordering and (VERY important) adds
> > more white space between the columns.
>
> I don't believe there was anything inconsistent.  It was always MLton,
> stable-MLton, old-MLton, and was right justified in a column.  The fix was
> simply to add the "-" characters, which should be enough.

I guess.  I agree with Henry that more whitespace would be useful.

Part of the naming confusion is my own fault for not overriding them.

Really, the issue is that the benchmark program isn't set up for comparing
the same compiler under different flags.