Qt: Add "Copy URI" to payment request context menu

src/qt/receivecoinsdialog.h

@@ -60,6 +60,7 @@ private:
     QMenu *contextMenu;
     const PlatformStyle *platformStyle;
 
+    QModelIndex selectedRow();
     void copyColumnToClipboard(int column);
     virtual void resizeEvent(QResizeEvent *event);
 
@@ -71,6 +72,7 @@ private Q_SLOTS:
     void recentRequestsView_selectionChanged(const QItemSelection &selected, const QItemSelection &deselected);
     void updateDisplayUnit();
     void showMenu(const QPoint &point);
+    void copyURI();
     void copyLabel();
     void copyMessage();
     void copyAmount();