- 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.
Fix a bug when after closing the settings window for a screensaver,
the preview for it wouldn't restart.
- Keep waiting for messages from the settings window while it's open
- Fix leaking two handles to avoid creating zombie processes
CORE-18680
Use window subclassing to override WM_PAINT message handling
and use RedrawWindow function along with WS_CLIPCHILDREN style
for the parent window in order to preserve screensaver drawing.
CORE-15929
