Added localized invalid name message

src/pocketmine/Player.php

@@ -1380,7 +1380,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 				}
 
 				if(strpos($packet->username, "\x00") !== false or preg_match('#^[a-zA-Z0-9_]{3,16}$#', $packet->username) == 0 or $this->username === "" or $this->iusername === "rcon" or $this->iusername === "console" or strlen($packet->username) > 16 or strlen($packet->username) < 3){
-					$this->close("", "Bad username");
+					$this->close("", "disconnectionScreen.invalidName");
 
 					return;
 				}