Creative Mines

This adds one base command: /af25. It has a few subcommands:

• level: A copy of the enabled-with-this-mod /level command allowing you to craft your mines
• unlock: Unlocks various things. Each of these has an all selector to unlock all.
  • world_effect: The world effects (the things you can customize about each mine)
  • special_mine: A special mine (with preset special world effects)
  • player_ability: Player unlocks (those which you find with the menu under U or the inventory). This has an optional extra parameter (defaulting to false) which if true will also unlock the "hard-knock" entries (bonus extra challenges)

This also re-enables creative mode in the world select screen.