* include/freetype/internal/ftpsprop.h: Use `FT_BASE_CALLBACK'.
(ps_property_get): Harmonize declaration with corresponding
function typedef.
* include/freety[e/internal/fttrace.h: Add `trace_psprops'.
* src/base/ftpsprop.c: Include necessary header files.
(FT_COMPONENT): Define.
(ps_property_set): Tag with `FT_BASE_CALLBACK_DEF'.
(ps_property_get): Tag with `FT_BASE_CALLBACK_DEF'.
Harmonize declaration with corresponding function typedef.
This reduces the amount of duplicated code across PostScript drivers.
* src/cff/cffdrivr.c, src/cid/cidriver.c, src/type1/t1driver.c
({cff,cid,t1}_property_{get,set}): Moved to...
* include/freetype/internal/ftpsprop.h: ...this new file.
(ps_property_{get,set}): New functions to replace moved ones.
* src/base/ftpsprop.c: Implement above functions.
* include/freetype/internal/internal.h (FT_INTERNAL_POSTSCRIPT_PROPS_H):
New macro.
* src/cff/cffdrivr.c, src/cid/cidriver.c, src/type1/t1driver.c: Updated.
* src/base/Jamfile, src/base/rules.mk, src/base/ftbase.c: Updated.