D19216: Karbon: Enable multi page capability

[René J.V. Bertin]

This would indeed be great to have; even a page selector when importing a multi-page document would be an improvement (the Adobe Illustrator version I've use had that; IIRC it would just leave all other pages of the document alone).

You should also test with PDF documents; in my experience Karbon 3.1 works well enough with them.

>Ported to use pageapp classes.
...
> A lot of code was duplicated between pageapp and karbon
> and has been removed from karbon:

Shouldn't that be a separate change - or does multi-page support come automatically with this change?