Git commits in Moodle 3.5.0 by Tim Schroeder

commit 1480277cfa37be86f312399ad77b4407d83c6b21
Author: Tim Schroeder <tim.schroeder.90@gmail.com>
Date:   Thu, 07 Dec 2017 21:23:16 +0800
Tag:    v3.5.0-beta

MDL-60681 lib/tablelib.php: Make flexible_table class better extendable