apply mb_strtolower to command_name in processUpdate
Keys in \Longman\TelegramBot\Telegram::$commands_objects get register as all lowercase, but not queried the same way. Apply mb_strtolower to $command_tmp in \Longman\TelegramBot\Telegram::processUpdate to short circuit \Longman\TelegramBot\Telegram::getCommandObject.
fixes #1197