from Kirigami 2.0 to 2.2 (theming change)

[Jan Mulder]

I have been looking to the possibility to upgrade of the import 
statement in QML for Kirigami. Currently, we are using 2.0 and I tested 
the upgrade to 2.2. Overall a positive step forward.

There is, however one change introduces changes on our side. For the 
interested reader, see Kirigami commit 5b08a7b6cd501e71c30. That (big) 
change is related to theming, and one construct in our main.qml is not 
allowed any more (for example: Kirigami.Theme.highlightColor = <our 
value>). These properties have become read only. Reading trough that 
commit, and code, I am still in the dark how to adapt our code.

Maybe Marco can shed some light on this subject?

-jan