Made MSW wxSpinCtrl emit UPDATE event when validating

the value in the text field upon kill focus.
 Documented this behaviour.
 This is in line with the GTK+ control.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41316 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/spinctrl.h

@@ -104,6 +104,9 @@ protected:
     void OnSetFocus(wxFocusEvent& event);
     void OnKillFocus(wxFocusEvent& event);
 
+    int m_oldValue;
+    virtual void NormalizeValue();
+   
     // the data for the "buddy" text ctrl
     WXHWND     m_hwndBuddy;
     WXFARPROC  m_wndProcBuddy;