fixes sorting on DataSetColumn Grid xibosignage/xibo#1620
fixes sorting on DataSetColumn Grid xibosignage/xibo#1620

xibosignage/xibo-cms,xibosignage/xibo-cms,dasgarner/xibo-cms,PeterMis/xibo-cms,dasgarner/xibo-cms,PeterMis/xibo-cms,alexharrington/xibo-cms,PeterMis/xibo-cms,alexharrington/xibo-cms,PeterMis/xibo-cms,dasgarner/xibo-cms,dasgarner/xibo-cms,dasgarner/xibo-cms,PeterMis/xibo-cms,xibosignage/xibo-cms,xibosignage/xibo-cms,xibosignage/xibo-cms,alexharrington/xibo-cms,xibosignage/xibo-cms,alexharrington/xibo-cms,alexharrington/xibo-cms,dasgarner/xibo-cms