Mode switching
First version of 'Stairway' tool
Give objects from hic a name
Fix: Don't delete containers during mode switch

One of obviously serveral bugs still there was: When we're recreating
the layout, we first empty the container and then insert new widgets
into it. But cleaning the container, marked it with deleteLater() since
it gets empty on the way.
Use the Stairway tool in the Tester
Mostly style changes
Fix saving of XmlStates
Add comment on behaviour