hooked up with CFF1 subroutinizer
a renaming

no-desubroutinize option is disabled for now
code cleanup (esp. CFF1 width handling)
bug fixes & renaming

clamp the value instead

Added OpCode_FontMatrix to TopDictOpSet (yet to parse values)
fixed a wrong assert in encode_int

Repurposed FDMap as Remap then subclassed for remapping SIDs
misc code cleanup

as they aren't instantiated with BlendArg (yet)

Templatized ArgStack so it may store the default value along with blend deltas as BlendArg while parsing blend operator arguments in CFF2 charstring
Added get_region_count() method to VarRegionList & VariationStore

Factored out CFF1 & CFF2 common subsetting code in hb-subset-cff-common.hh