After various requests, I decided to implement support for MySQL databases, so data can be shared thru a network instead of just one server.
The official test server is now online via the IP "ultimatestatistics.vagdedes.me". Building, Killing, Farming and anything else is allowed to let your statistics fully grow.
Logs:
Implemented a new configuration system. (mysql.yml)
Implemented database support as a way to save stats.
Removed an unneeded unregistered listener.
Implemented a new settings.yml option. (log_mysql)
Implemented new methods to the Math utilities.
Corrected a 1.13 ore-block material console-error.
Corrected an inventory-item description bug.
Disabled the Top-Player feature when using a database.
Corrected a bug that prevented data from being properly cleaned.
Slightly improved the saving handlers with faster codes.