Received the following error when using the PDF Submission plugin:

Strict standards: Declaration of assign_submission_pdf::get_files() should be compatible with that of assign_plugin::get_files() in /var/www/moodle/mod/assign/submission/pdf/locallib.php on line 788

This very minor edit prevents the error appearing simply by replicating the expected passed objects.
Merge pull request #1 from vaughany/master

PHP strict standards warning and fix