Adding dehumanize_number to libutil

[Eitan Adler]

Hi all,

NetBSD and DragonflyBSD have a function dehumanize_number which is the
inverse of humanize_number.

I'd like to import this function and switch some base utilities to use
it.  Is there any objection?

Patch is here: http://people.freebsd.org/~eadler/files/dehumanize.diff
 This implemtation is a direct copy of DragonFlyBSD's version.

-- 
Eitan Adler