rolled the parts of the new core back together into one file...
just one configuration line in the make file to enable/disable.

	modified:   simavr/Makefile
	modified:   simavr/sim/sim_avr.c
	deleted:    simavr/sim/sim_core_v2.c
	deleted:    simavr/sim/sim_core_v2.h
	deleted:    simavr/sim/sim_core_v2_flag_ops.h
	deleted:    simavr/sim/sim_core_v2_inst_ops.h
	deleted:    simavr/sim/sim_core_v2_mem_funcs.h
	modified:   simavr/sim/sim_core_v3.c
	deleted:    simavr/sim/sim_core_v3.h
	deleted:    simavr/sim/sim_core_v3_inst_ops.h