APIs for adding a thumbnail toolbar with a specified set of buttons.

- AddThumbBarButton(wxThumbBarButton *button), ShowThumbnailToolbar().
- Add THBN_CLICKED message handler to top level window and generate a
  wxCommandEvent event.
- Sample.

Author: Chaobin Zhang

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77594 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/toplevel.h

@@ -146,6 +146,8 @@ public:
     // deleted when the window itself is, do not delete it yourself. May return
     // NULL if the initialization of taskbar button failed.
     wxTaskBarButton* MSWGetTaskBarButton();
+
+    bool HandleTHBNClickedCommand(WXWORD id);
 #endif // wxUSE_TASKBARBUTTON
 
 protected: