Move themes to PreferenceEditor

include/editor.h

@@ -65,7 +65,6 @@ public:
     void displayMapBorder();
     void displayMapGrid();
     void displayWildMonTables();
-    void maskNonVisibleConnectionTiles();
 
     void updateMapBorder();
     void updateMapConnections();
@@ -154,6 +153,9 @@ public:
     void shouldReselectEvents();
     void scaleMapView(int);
 
+public slots:
+    void maskNonVisibleConnectionTiles();
+
 private:
     void setConnectionItemsVisible(bool);
     void setBorderItemsVisible(bool, qreal = 1);