Players without cooldowns will not be able to stuff the level queue with
calculation requests. Only one island level calculation at a time.
Watch dog timeout on calculations added. Default 5 minutes.
Config option to not use island zeroing.
* Stores level data on a per island basis
* Migrate after BentoBox worlds have loaded.
* Added new Admin set initial level handicap command
* Bug fixing
* Fix test
* Removed code smell
