Ship names

Redone a lot of the ship names to be more logical, and added names for ships that were just "ship". Also changed the police and military ship to not be available for purchase, and adjusted lots of the ship prices.

The rest of the ship stats still need to be balanced, which I've still not got around to, but will soon :)

Hopefully no mistakes have gotten through but a lot of ship defs and files have been changed so something may have gotten through.