Fix Mappings in PictureViewer2

Another fix for the new MappingTreeModel database layout: Make the
mappings display correctly when showing an archived picture.

For performance reasons I had to make PicFilesModel global and put it
into a separate file.

Also clean up MappingTreeModel: remove comments and unused functions.

1 files changed, 1 insertions, 1 deletions

diff --git a/mappingtreewidget.cpp b/mappingtreewidget.cpp
index 82a1490..92366e0 100644
--- a/mappingtreewidget.cpp
+++ b/mappingtreewidget.cpp
@@ -92,7 +92,7 @@ MappingTreeWidget::MappingTreeWidget(QWidget *parent) : QWidget(parent){
 }
 
 MappingData MappingTreeWidget::selectedItem() const {
-    MappingData retval = { -1, QString(), QStringList() };
+    MappingData retval = { -1, QString(), QList<QStringList>() };
     QModelIndex sel = selected();
     if(!sel.isValid()){
         return retval;