Add a config section with debug and cleanup toggles to tasks

It's now possible to set if you want the debug output of all api calls
and want the created tasks deleted at the end of the file.
Implemented new setSubTaskParent api call to add or remove a parent

Described by the api update as:
Subtask re-homing. You can set the parent field on a Task to change which Task
it is a subtask of.

Use 'null' to remove a parent from a subtask with setSubTaskParent

Allow removal of a parent from a subtask to make it a normal task by
using 'null' for the parent value. This needs to be quoted, otherwise
the parent field will be removed from the body and the API will return
a 400 bad request