- All player-facing chat texts moved into a language file (messages_<language>.yml),
fully editable, with '&' colour codes and formatting supported on every line.

- New config option 'language' selects which messages file is loaded (default en);
a missing file or line falls back to the built-in English defaults.

- config.yml now self-updates on start: options added in a newer version are inserted
into an existing config automatically - your values and comments are kept, and a
config.yml.bak backup is written first. No more deleting the config after an update.

- Console/log messages and the name-colour system are unchanged.