fast core incorporated into run_avr & bug fixes.

run_avr: fast core incorporated into run_avr with switch -fast-core
	makefiles modified to be nearer to stock simavr.
sim_avr: code additions for fast core no longer needed as rolled into run_avr.
sim_fast_core: bugfixes revealed by avr instruction and timing test
	programs written by Shay Green.

	modified:   Makefile.common
	deleted:    examples/board_fignition/FIGsimavr.c
	deleted:    examples/board_fignition/Makefile
	modified:   simavr/Makefile
	modified:   simavr/sim/run_avr.c
	modified:   simavr/sim/sim_avr.c
	modified:   simavr/sim/sim_core.c
	modified:   simavr/sim/sim_fast_core.c