- Introduce AddScreenSaver[Item] helpers for adding screensavers in
the list (either given by file path or by item structure).
- Rename "AddScreenSavers" to "EnumScreenSavers", and
"ScreenSaverItem" type to "SCREEN_SAVER_ITEM".
- Ensure the stored "SCRNSAVE.EXE" value is NULL-terminated.
- Add the current screensaver, specified by the "SCRNSAVE.EXE" registry
value, in the list if it isn't already present; otherwise select it
in the list.
- Make the filename comparison case-insensitive.