Tweak per-face LCD filtering controls.

Thing are simpler with a NULL-function pointer.

* include/freetype/internal/ftobjs.h (FT_Face_InternalRec): New
pointer to the filter function.
(FT_LibraryRec): Remove unused `lcd_filter'.
(FT_Bitmap_LcdFilterFunc, ft_lcd_filter_fir):  Move from here...
* include/freetype/ftlcdfil.h (FT_Bitmap_LcdFilterFunc,
ft_lcd_filter_fir): ... to here.

* src/base/ftobjs.c (ft_open_face_internal): NULL-initialize the
per-face filter.
(FT_Face_Properties): Set it.
* src/smooth/ftsmooth.c (ft_smooth_render_generic): Simplify.

* src/base/ftlcdfil.c (ft_lcd_filter_fir, FT_Libary_SetLcdFilter):
Minor.
6 files changed