:16170829 'Displays a file dialog with the supplied filter, default extension, dialog title, and save/open style.
'filt: A filter of the form "label|extension|label|extension|..." where label is text user sees and extension is *.something
'def: The file extension to add to a save dialog if the user doesn't supply any extension on their own. Omit the period.
'title: The dialog box title to display to the user.
'save: A boolean value (true or false) - if true, display a save dialog. If false, display an open dialog.