[autofit] Rename 'ft-hb' to 'ft-hb-ft'. Since it's a (shrinked) copy of 'hb-ft'. * src/autofit/afglobal.c (af_face_globals_new), src/autofit/afshaper.h, src/autofit/autofit.c: Updated. * src/autofit/ft-hb.c, src/autofit/ft-hb.h: Renamed to... * src/autofit/ft-hb-ft.c, src/autofit/ft-hb-ft.h: ...this; updated. * src/autofit/rules.mk (AUTOF_DRV_SRC): Updated.