GUI improvements found during #707

* logs only screen in core as default
* find top window, only use Qt::WA_TranslucentBackground on top level (Qt 5.6.1)
* correct presize when insert
* resize ATC when first station is added

src/blackgui/guiutility.h

@@ -104,6 +104,9 @@ namespace BlackGui
         //! Only the row part and unique (so no rows is twice in the list)
         static QList<int> indexToUniqueRows(const QModelIndexList &indexes);
 
+        //! Is top level widget?
+        static bool isTopLevelWidget(QWidget *widget);
+
     private:
         //! Constructor, use static methods only
         CGuiUtility() {}