Created a separate logging class. Moved import code into own class.
Created a ConfigurationKeys class holding all config keys as static strings. Refactored many classes now using the ConfigurationKeys class.
Refactoring for the Language class: Removed the plugin attribute. Changed a method name.
Moved some classes into a new persistence package.
Fixed a typo.
Removed unused methods.
Refactoring: Moved inventory loading and saving methods into own class.
Refactoring: Moved stats loading and saving methods into own class.
Simplified the SaveTask class.
Refactoring: renamed the SaveTask to InventorySaveTask.
Refactoring: renamed the WordlInventories class to Plugin.
Fixed some warnings. Improved error handling.