New features:
	Water now completely removed from falling ships
	LaunchTorpedoes now sink at the end of their flight
	overallSinkPercent - if below this percent of the original blocks
remain, the craft will sink
	sinkSpeed - the speed at which the craft will sink
	keepMovingOnSink - if set, the craft will continue to move in its last
movement direction as it sinks
	explodeOnCrash - strength of the explosion when the craft crashes
	smokeOnSink - if set to 1, smoke will come from the crashing craft