nsf.c: - new cmd for debugging: nsf::__db_show_obj - added MethodDupInternalRep() and FlagDupInternalRep() since they appear to be required in Tcl 8.6b2.
- reform of argument parse. new parser uses NsfFlagObjType to reuse earlier parse resuslts. Improved speed for for methods with primitive bodies: 5%-25%.