watchdog: updates and corrections based on requests

fix style error(s)
change rename 'after_reset' to 'reset_context'
add type avr_run_t

	modified:   simavr/sim/avr_watchdog.c
		renamd 'after_reset' to 'reset_context'

	modified:   simavr/sim/avr_watchdog.h
		renamd 'after_reset' to 'reset_context'
		style correction
		changed avr_run

	modified:   simavr/sim/sim_avr.h
		added avr_run_t...
		updated 'avr_t.run' accordingly
watchdog: ammendment, dont clear data on reset.

definitive details on reset behavior is fuzzy...
some agreement that ram is not cleared during reset and
there being some suggestion that registers and or io registers
may be cleared...  compromise by clearing just the lower
register and io region...  data is cleared during init at least.

	modified:   simavr/sim/sim_avr.c