Make `FT_Set_Named_Instance' work.

* src/cff/cffdrivr.c (cff_set_instance): New function.
(cff_service_multi_masters): Register it.

* src/truetype/ttgxvar.c (TT_Set_Named_Instance): New function.
* src/truetype/ttgxvar.h: Updated.
* src/truetype/ttdriver.c (tt_service_gx_multi_masters): Register
it.

* src/type1/t1load.c (T1_Reset_MM_Blend): New function.
* src/type1/t1load.h: Updated.
* src/type1/t1driver.c (t1_service_multi_masters): Register it.
8 files changed