Fix wrong added nodes in FolderTreeModel (and changes sorting order)
Fix wrong added nodes in FolderTreeModel (and changes sorting order)

The method UpdateFolderTree expects ASC as sorting order of the URIs,
otherwise URIs can be added at wrong nodes of the tree. Changing
the order to ASC fixes this and now the usual sorting order is used
('a' before 'b').

Yetangitu/f-spot,mans0954/f-spot,nathansamson/F-Spot-Album-Exporter,Sanva/f-spot,mono/f-spot,Sanva/f-spot,mans0954/f-spot,NguyenMatthieu/f-spot,nathansamson/F-Spot-Album-Exporter,GNOME/f-spot,Yetangitu/f-spot,nathansamson/F-Spot-Album-Exporter,GNOME/f-spot,Yetangitu/f-spot,mans0954/f-spot,dkoeb/f-spot,Yetangitu/f-spot,mono/f-spot,mono/f-spot,NguyenMatthieu/f-spot,nathansamson/F-Spot-Album-Exporter,NguyenMatthieu/f-spot,Sanva/f-spot,Sanva/f-spot,mono/f-spot,dkoeb/f-spot,dkoeb/f-spot,GNOME/f-spot,dkoeb/f-spot,mono/f-spot,mans0954/f-spot,mans0954/f-spot,Sanva/f-spot,mans0954/f-spot,Yetangitu/f-spot,GNOME/f-spot,NguyenMatthieu/f-spot,dkoeb/f-spot,NguyenMatthieu/f-spot,GNOME/f-spot,mono/f-spot,dkoeb/f-spot