add worldsize option to seedfile

[akariley]

add ability to specify optional worldsize value to seedfile
eg,

1125345623 5000

[akariley]

thoughts: check for ^'numbers' ' space' '[optional numbers]'$

If there's no numbers after a space, truncate the space and use the number as a seed. If there are numbers, check if they fit the size values (1k - 6k).

[akariley]

Could also use this to use a custom map as well. Maybe an optional parameter to specify the amount of wipes to use the map?