StatusLabel: flickerless paint
PlaylistBar: drag and drop deeply nested folders

Support it.
Discard .ini cache when it's not being accessed

Refs #4193
Flush .ini cache after idle processing is done
Use the right prefix for bool variable
Construct CAppSettings in InitInstance()

It allows us to use COM objects in CAppSettings ctor.
FileAssoc: don't use static methods
FileAssoc: don't use static variables
Reduce header dependencies
Cosmetics

Placed 'extern' functions together.
Marked local functions as 'static'.
And some minor clean-ups and cosmetics.
Use 'override' keyword
A bit more sane hooks declaration
Simplify setting heap information
VSFilter/ISR: Fix override placement not being applied even if enabled.

ISR: Fix subtitle default style being lost after changing default style in settings.

Fixes #34.
VSFilter: Pass through dwTypeSpecificFlags and dwInterlaceFlags.

This fixes interlaced videos.

Fixes #2671
Repaint video frame when toggling statistic.
RTS: Fix outline size when using default style for ASS subtitles.

Fixes #3701
RTS: Add some rounding to ensure higher precision.
RTS: Preserve proper subtitle positioning and constant font size for default style override along different subtitle files.

Fixes #1574
RTS: Don't remove subtitles effect when default style is applied.

"Default Style" option is to apply default style for subtitles and not
actually completely break them.

Fixes #4171