bugs:
	https://mods.factorio.com/mod/cybersyn/discussion/63a52e54be4341bccc0446f8

major:
	debug output
	add in game guide
	move to an event based algorithm
	models & art
	train always returns to same depot setting
	make train inactivity condition a setting

minor:
	handle if signals are removed from the game during migration
	railloader compat
	close gui when the combinator is destroyed
	do not play close sound when a different gui is opened
	gui can desync if settings are changed outside of it while it is open
	give the combinators a sensible reaction to low or no power
	picker dollies compat?