Fix #705

Idk why the player becomes null, maybe the isOnline check is enought

src/main/java/fr/xephi/authme/listener/AuthMePlayerListener.java

@@ -444,8 +444,11 @@ public class AuthMePlayerListener implements Listener {
         Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
             @Override
             public void run() {
+                // Fix NPE, idk how this is possible -sgdc3
+                if(player != null && player.isOnline()) {
                     player.closeInventory();
                 }
+            }
         }, 1);
     }