more optimized flag operations

	modified:   simavr/sim/sim_core_v2.c
	modified:   simavr/sim/sim_core_v2_flag_ops.h
	modified:   simavr/sim/sim_core_v2_inst_ops.h
	modified:   simavr/sim/sim_core_v2_mem_funcs.h
	modified:   simavr/sim/sim_core_v3_inst_ops.h