I have installed Opigno on a Ubuntu Xenial server (PHP 7.0) for the first time but if refuses to recognise installed software. I have installed pdf.js and wkhtmltopdf following the user manual and ffmpeg from the repo. The status report says that pdf.js is not installed. Also the PDF configuration page admin/config/user-interface/print/pdf doesn't mention wkhtmltopdf as an option and the page /admin/config/media/video/transcoders doesn't exist. Is this problem related to PHP 7.0?