Added in the hardcore game mode

Added in the ability to run a hardcore server.
All you need to do is type ./starmaded.sh hardcore, it will generate a
small config file called starmadedhardcore.cfg. You may edit this to
your liking before using ./starmaded.sh hardcore again, and the sector
list generation will begin (may take a little while)
To actually start the server then, all you need to do is change
HARDCORE=NO in starmaded.cfg to HARDCORE=YES and then restart the
server, and the hardcore spawning method will begin.
Any spawned ships will be despawned after 24 hours, and even if a player
is inside a sector when the spawning is triggered, they wont affect it.