Update 1.15.0

- Some code optimization
- Added Nukkit support
- Added invalid-ip in config
- Fixed bug: IP is not check when a player join with a new IP
- Disabled max IP check on invalid IPs

Warning config.yml file changed in this version! It's important to make a new one or add news in the current file. It's important to avoid any bug.

Changes:
Added: invalid-ip: true, and invalid-ip in messages
Changed: vpn.kick to kick (same for ban, notify), max-ip section changed too.

(You can see the last config file on the presentation page)
(Invalid IPs are local, and private address)