Additions:
- Added a config setting to enable a permission to open the spawner menu.
- Added a config setting to enable a permission to open the upgrade tree menu inside of the spawner menu.

General Changes:
- Made some changes to the backend to improve performance very slightly.
- Changed a lot of the logger messages to correctly use the plugin logger instead of bukkits built in logger.

Fixes:
- Fixed the break permission being used when placing spawners.
- Fixed the 'BreakSpawnerPermissions' configuration setting not being checked.
- Fixed permission not being checked when placing natural spawners.
- Fixed an issue where spawners from other plugins, or from commands would generate as 'invalid spawners' due to them not having the correct data tags.
- Fixed an issue where spawner trees with invalid spawners would cause issues, making the tree unable to be modified or edited in-game.
- Fixed an issue with creating new Spawner Trees
- Fixed an issue relating to tab completion with the giveUpgradedSpawner command.
- Fixed an issue relating to the saving of spawner trees.