Change the sorting for due date

[arpsoid]

In the present version sorting for due date is working fine apart from the fact that it orders tasks without due date before tasks with due date. Please consider switching this to alternative order, where tasks with due date are listed before the tasks without due date. Thank you!

[fuchsmich]

Thank you for reporting. I guess tasks without due date should always be at the end of the list, no matter if ascending or descending order is selected.