The sdf module wasn't recognized, so the generated ftmodule.h had "None_renderer_class".
* builds/meson/parse_modules_cfg.py: Handle sdf in RASTER_MODULES.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration values
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW`,
`FT_COLR_PAINTFORMAT_INTERNAL_SKEW_CENTER`, and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW_CENTER`.
(read_paint): Handle new enumeration values.