sort with a tab as separator

[Guy Harris]

>Improved: it is command-line and history editing via Emacs commands that
>probably screws up some of this. I am VERY GLAD that the NeXT csh has this
>feature. It makes life much more pleasant. In fact, I wouldn't even consider a
>shell without this feature.

And *I* wouldn't consider a shell that turned tabs into spaces, even
though I like that kind of command-line and history editing.  "ksh" has
command-line and history editing via EMACS commands, and as I remember
it didn't have any such problems; the Bourne-again shell version here
also has command-line and history editing via EMACS commands, and *it*
doesn't have that problem.