'SORTLS' by Joe Horn; *quickly* sorts a list of strings into alphabetical
order.  Be sure only to use a list of STRINGS as the input to this routine;
any other objects in the list will cause undesirable results.

Also see SORTLN on this disk if you wish to sort a list of numbers.

SORTLS uses the entry point at #1420Ah, which is the System RPL
command that compares two strings like the User Rpl ">" does.
It works in ROM versions A through J, but may not work in future
versions of the HP48.

Thanx to Brian Maguire and Mike Morgan for concepts used here.