Updated link to PHPExcel library
Updated link to PHPExcel library

On Codeplex we find this message:
    2015-08-10 Friendly Reminder!
    We moved to https://github.com/PHPOffice/PHPExcel over 3 years ago
    The site here on codeplex is no longer current
mikifus/data-import,gnat42/data-import,ddeboer/data-import,ptorti/data-import