misc:
	GuiTraceRay does not stop at water surface anymore by default
	(all ground-attack positions are adjusted in synced code now)
	--> torpedo launchers cannot overshoot, etc.

	change WorldObject::speed to a float4, store magnitude in .w
	(saves a number of unnecessary .Length() calls here and there)

	make all assignments to speed.xyz go through SetVelocity, but
	for efficiency reasons calculate .w through SetSpeed (because
	there can be many SetVelocity()'s per function and usually only
	the final vector matters)

	LuaOpenGL::Draw{List,Func}AtUnit: just use drawPos or drawMidPos