New option for ls(1), du(1), df(1)

[Mike Karels]

> > I've hacked a new option into those tools which uses
> > thousands separators for displaying the numbers.

> Perhaps you want to hack humanize_humber(3) instead, which a great deal of
> tools use.

Maybe humanize_number could look at an environment variable that describes
what the human wants :-).

		Mike