Readds large crossbow to the protolathe

I didn't want this code to go unused, so this readds the large crossbow to the protolathe with:

-New sprites
-New descriptions
-New prices

And it is fairly simple to distinguish the two, so I do not believe there will be "HOLY SHIT TRAITOR LYNCHMOB GO" if someone happens to build one of these with recovered syndie tech.