Database export excel fix

Bug fix - türkçe karakterlerin çözümü

    header('Content-Encoding: UTF-8');
    header("Content-Type: application/xls");
    header( "Content-disposition: attachment; filename=".$filename."");
    header("Pragma: no-cache");
    header("Expires: 0");
    header('Content-Description: File Transfer');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Pragma: public');