along with CFF2 charstring interpreter
factored out common code between CFF1 & CFF2 to CSInterpreter
moved fetch_op from Interpreter to InterpEnv
misc code clean up & bug fixes
Unreferenced subroutines are nullified (not removed) in a subset font
Separate Interpreter struct from hb-ot-cff-common-private.hh in a set of four header files, augmented for CharString (CS):
hb-cff-interp-common-private.hh
hb-cff-interp-dict-common-private.hh
hb-cff-interp-cs-common-private.hh
hb-cff-interp-cs.hh
Interpreter runtime is separated off as a new struct InterpEnv sub-classed differently for Dict and CharString (CS)
Added a set of sources hb-subset-cff-common-private.cc & .hh for FDSelect subseting code.
Added FDSelect format 4 (CFF2 only) support. Shared its implementation with format 3 as a template.
Instead moved & stored uniformly in values vector (renamed from opstrs)
This should be fine as we aren't likely going to use them as hints after all
Templatized DictValues whether to parse them out
For subsetter, they aren't parsed
Michiharu Ariza