* Move initial batch of shaders and presets to smoothing subdirectory
* Rename smoothing to edge enhancement
* Move cubic and windowed into interpolation
* Fix some presets
* Fix rest of presets
* Rename edge-enhancement to edge-smoothing
* Move pixel art scalers into separate directory separate from 'interpolation'
* Flatten interpolation/cubic into interpolation/
* fix preset parsing issues from https://github.com/libretro/slang-shaders/issues/369
* one more preset fixed
* fix some malformed preset directives
* fix preset lines erroneously ending in semicolons
* fix another malformed preset directive
* make sure grade and glass at least load properly
* comment one more bad path
* fix reference pass for old scalefx in sh1nra ntsc
* fix reference pass for scalefx in sh1nra vibrance
* fix reference pass for old scalefx
* fix reference pass for old scalefx-9x
