Add markup support to wxMSW wxButton and show it in the sample.

Use recently added wxMarkupText to implement support for markup in wxMSW
wxButton.

Update the button page of the widgets sample to show markup support.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67065 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/button.h

@@ -85,6 +85,10 @@ protected:
     virtual void DoSetBitmapMargins(wxCoord x, wxCoord y);
     virtual void DoSetBitmapPosition(wxDirection dir);
 
+#if wxUSE_MARKUP
+    virtual bool DoSetLabelMarkup(const wxString& markup);
+#endif // wxUSE_MARKUP
+
     // Increases the passed in size to account for the button image.
     //
     // Should only be called if we do have a button, i.e. if m_imageData is
@@ -93,6 +97,10 @@ protected:
 
     class wxButtonImageData *m_imageData;
 
+#if wxUSE_MARKUP
+    class wxMarkupText *m_markupText;
+#endif // wxUSE_MARKUP
+
     // true if the UAC symbol is shown
     bool m_authNeeded;
 
@@ -100,6 +108,9 @@ private:
     void Init()
     {
         m_imageData = NULL;
+#if wxUSE_MARKUP
+        m_markupText = NULL;
+#endif // wxUSE_MARKUP
         m_authNeeded = false;
     }