Bug fixes and other basic improvements

Should be basically uncontroversial.

I wasn't entirely sure about removing certain unused ship info from the shipyard in dec0ac2, because it seems this stuff *can* be used, but just isn't anymore. I took the fact that the Schroedinger had its massive fuel tanks removed as a clue that these parts of the ship info are obsolete. Please let me know if I made a bad judgment here.