[gnome-todo] (11 commits) Created branch wip/gbsneto/subtasks

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

The branch 'wip/gbsneto/subtasks' was created.

Summary of new commits:

  12cec1f... task: add subtask support
  58205eb... provider-eds: remove task list from internal storage
  8fe3e08... task-list: proccess subtasks
  4c8043d... task-row: simplify xml file
  caef5fe... task-row: implement subtasks with DnD
  ed8da62... task: add ::is_subtask() API
  efb3d66... task-list: emit ::list-changed whenever a task changes
  2357967... task-list-view: sort listbox when list changes
  af558ce... task: add ::depth property and API
  80102da... task: consider subtask tree when sorting
  bd8764d... task-row: forbid making a parent task a subtask of a subtas