#40 Quick hierarchy change in Atlas Content pane

[Jiri Tusla]

In the Altas content pane there is a hierarchy
Atlas
- Region1
--Zoom1
--Zoom2
- Region2
--Zoom1
--Zoom2
- Region3
--Zoom1
--Zoom2

Please implement a button/pop-up menu item/.. which do a
transposition to the form
Atlas
-Zoom1
--Region1
--Region2
--Region3
-Zoom2
--Region1
--Region2
--Region3

This becomes handy when creating atlases for non rectangular
areas by stripes of squares, square,etc.

THX!