Move gamemode stuff to listener

- Fix messages in messages.yml not being used
- Fixed checkRank not working
- Added permissions support for tab handing

src/main/java/dev/plex/command/impl/DeopCMD.java

@@ -22,7 +22,7 @@ public class DeopCMD extends PlexCommand
     {
         if (args.length != 1)
         {
-            return usage(getUsage());
+            return usage();
         }
         Player player = getNonNullPlayer(args[0]);
         player.setOp(false);