Add DoubleJumpListener fly detection

src/de/steamwar/lobby/listener/DoubleJumpListener.java

@@ -69,8 +69,8 @@ public class DoubleJumpListener implements Listener {
     public void handlePlayerMove(PlayerMoveEvent event) {
         Player player = event.getPlayer();
 
-        if(player.getLocation().add(0, -1, 0).getBlock().getType() == Material.AIR)
+        if(player.getLocation().add(0, -1, 0).getBlock().getType() == Material.AIR) return;
-            return;
+        if (LobbyPlayer.getLobbyPlayer(player).isFly()) return;
 
         player.setAllowFlight(true);
         if (player.getGameMode() == GameMode.ADVENTURE || player.getGameMode() == GameMode.SURVIVAL) {