2.5.1
- Repair the new player functionality
    - tracks a new player via the 'hasPlayedBefore()' method, then listens for them to change world before triggering aNewPlayer custom event
    - notifies owners of the 'Tours.notify.newplayer' node, and displays a welcome message to player
- Simplified pom
- Added empty 'authors' field to plugin.yml for contributors
- Tweaked tour join message