API for change the visibility of button in the taskbar.

- ShowInTaskbar and HideInTaskbar
- Sample of usage.

Author: Chaobin Zhang

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77573 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/taskbarbutton.h

@@ -21,6 +21,8 @@ public:
     virtual ~wxTaskBarButtonImpl();
 
     virtual void SetProgressValue(int value) wxOVERRIDE;
+    virtual void ShowInTaskbar() wxOVERRIDE;
+    virtual void HideInTaskbar() wxOVERRIDE;
 
 private:
     friend class wxTopLevelWindowMSW;