remove calls to marpa_g_symbol_nulled_event_set() from grammar construction
remove calls to marpa_g_symbol_nulled_event_set() from grammar construction

jeffreykegler/libmarpa,pczarn/kollos,pczarn/kollos,jeffreykegler/libmarpa,jeffreykegler/kollos,pczarn/kollos,jeffreykegler/libmarpa,jeffreykegler/kollos,jeffreykegler/kollos,pczarn/kollos,pczarn/kollos,jeffreykegler/kollos,jeffreykegler/libmarpa,jeffreykegler/kollos,jeffreykegler/libmarpa