Switch to side-by-side view

--- a/src/qtgui/restable.h
+++ b/src/qtgui/restable.h
@@ -132,6 +132,7 @@
     virtual void readDocSource(bool resetPos = true);
     virtual void onSortDataChanged(DocSeqSortSpec);
     virtual void createPopupMenu(const QPoint& pos);
+    virtual void onDoubleClick(const QModelIndex&);
     virtual void menuPreview();
     virtual void menuSaveToFile();
     virtual void menuSaveSelection();