ReportRun.php contains 13 calls to deprecated "split" function

"split" was deprecated in PHP-5.3 and REMOVED in PHP-7 according to this:

http://php.net/manual/en/function.split.php

Yet in http://code.vtiger.com/vtiger/vtigercrm/blob/master/modules/Reports/ReportRun.php there are at least 13 calls to it.