in list view tasks should inherit properties of subtask

[Solar-Simon]

when working with subtask, sometimes I use it for projects with several steps.
If the parent task has a date, it is sorted by this reference by the smart sorting.
Also this date is shown in your lists.

But the project date may be the final date to finish this project, while subtasks must be done earlier and maybe higher priority.

So the displayed date and priority in the list should be the earliest date and highest priority of any task (parent or sub)