Bug version 3.1.9

Correct the config / mimes file because it does not read the pptx file properly

I solved this way:


 'ppt' => array('application/powerpoint', 'application/vnd.ms-powerpoint', 'application/vnd.ms-office', 'application/msword'),
 'pptx' => array('application/vnd.openxmlformats-officedocument.presentationml.presentation', 'application/zip', 'application/msword','application/vnd.ms-powerpoint'),