Finally implementing in-game functions for managing worlds/sub-worlds! Renaming files will become unnecessary.
Make World/Server Auto - makes the selected world/server data automatic for the current world/server. Useful when servers change IP but you don't use a domain name to connect.
Make Sub-world Auto - makes the selected sub-world data automatic for the current sub-world. Useful when servers mess up multi-world detection.
Delete World/Server - deletes the whole data folder for the selected world/server.
Delete Sub-world - deletes the selected sub-world file.