Rewritten the GUI adding items system. Now you can use MiniMessage in GUI items.
Fixed /duels accept command bug.
Added new permissions for every player-duel command. You can enable/disable them from config, you can use this to set cooldowns on duel command.
Fixed that arena would still appear in Arena selector GUI if you deleted it with a command.
Fixed that it would ignore your blocked-or-allowed commands in the 10 second cooldown teleporting to spawn.