[KPhotoAlbum] Super categories makeover

[Tobias Leupold]

Hi list!

I'm just about doing something concerning Bug #237846. I opened the new branch 
"supercategories" for this. It's not yet a lot, but please have a look at it, 
before I go on in a wrong direction.

I added a QTreeWidget to the SubCategoriesPage, along with two functions 
translating the current two-level hierarchy of super- and subcategories in a 
tree hierarchy, which is then added to the QTreeWidget.

Is it okay to do it in this way? If so, "all" that has to be done is renaming, 
drag-and-drop support and adding new sub-categories.

Yours, Tobias