[win32] Software linear filtering

[eugene-s-nesdev]

Old emulators and DirectDraw hardware blitter:
narzoul/DDrawCompat#104

Most of FCEUX filters requires keep "hardware acceleration" enabled for best-looking (especially if you're use TV-aspect ratio).
Win32-build does hardware blitter (linear interpolation) via DirectDraw instead of D3D.

Recent Nvidia video drivers doesn't have DirectDraw hardware blitting support since Windows 7,
but intel GMA/HD graphics does. Linear interpolation works even on Windows 10 here.

This is an old issue, and Nvidia don't want to fix it yet:
https://www.nvidia.com/en-us/geforce/forums/discover/33537/pixalisation-with-directdraw-blt-under-vista-pixel-replication-instead-interpolation/

Feature request: add the global software linear filter to win32 build that can be mixed with other filters.

intel (DirectDraw linear interpolation works correctly):

nvidia (DirectDraw linear interpolation doesn't work):

[eugene-s-nesdev]

Respect to narzoul, DDrawCompat developer: