Fixed /mm butcher command
Optimisations to DespawnTask + Player tracking

- The despawn task can now be run in Async preventing the main thread
from bring bogged down (Beta)
- The Despawn task also spreads itself over serveral ticks to prevent
the main thread from being bogged down (For both Sync and Async
versions)
- Player Tracking has been optimised by only updating layers when a
player moves from a layer boundary.
- Added settings to make the despawner task to ignore tamed animals +
make tamed animals not count towards animal limits
- Added a new method to protect farm animals from the despawner