This reduces redundancy and increases synergy; it also reduces the
number of header files.
* include/freetype/config/ftheader.h (FT_DRIVER_H): New macro.
(FT_AUTOHINTER_H, FT_CFF_DRIVER_H, FT_TRUETYPE_DRIVER_H,
FT_PCF_DRIVER_H, FT_TYPE1_DRIVER_H): Make them aliases to
FT_DRIVER_H.
* include/freetype/ftautoh.h, include/freetype/ftcffdrv.h,
include/freetype/ftpcfdrv.h, include/freetype/ftt1drv.h,
include/freetype/ftttdrv.h: Replaced with...
* include/freetype/ftdriver.h: ...this new file.
(FT_CFF_HINTING_ADOBE, FT_T1_HINTING_ADOBE): Renamed to...
(FT_HINTING_ADOBE): ... this new macro.
(FT_CFF_HINTING_FREETYPE, FT_T1_HINTING_FREETYPE): Renamed to...
(FT_HINTING_FREETYPE): ... this new macro.
* src/*/*: Updated accordingly.