Usage: [options] InFileName OutFileName
-A (allow adding destination items)
-CD "Caption of Destination List"
-CS "Caption of Source List"
-Hn (Sets the height)
-Ln (Sets the Left screen position, default is centered)
-Sn Skip the first n lines of InFileName
-SO Sort OutFileName
-T "DualList Title"
-Tn (Sets the Top screen position, default is centered)
-Wn (Sets the width)
DualList loads InFileName into the left side of a dual list box.
If OutFileName exists, it is loaded into the right list and removed from the left.
If an item in the right list does not exist in the left list, it is deleted.
User selects one or more items from the left side to add to the right list.
If the user clicks the OK button with one or more items selected, the right list
is written to OutFileName. If no items selected, OutFileName is deleted.
If the Cancel button is clicked (or the program is closed without clicking
the OK button), OutFileName is deleted.