provide Do[GS]etColumnsOrder() stubs for the generic wxHeaderCtrl

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57234 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/headerctrlg.h

@@ -56,6 +56,9 @@ private:
 
     virtual void DoScrollHorz(int dx);
 
+    virtual void DoSetColumnsOrder(const wxArrayInt& order);
+    virtual wxArrayInt DoGetColumnsOrder() const;
+
     // override wxWindow methods which must be implemented by a new control
     virtual wxSize DoGetBestSize() const;
 
@@ -129,6 +132,10 @@ private:
     // the overlay display used during the dragging operations
     wxOverlay m_overlay;
 
+    // the indices of the column appearing at the given position on the display
+    // (its size is always m_numColumns)
+    wxArrayInt m_colIndices;
+
 
     DECLARE_EVENT_TABLE()
     DECLARE_NO_COPY_CLASS(wxHeaderCtrl)