Called by the framework when Excel creates a new workbook
[C++]
virtual void OnNewWorkbook(
   LPDISPATCH dispWorkbook
);
Pointer to dispatch interface of class Excel.Workbook.
This function is called whenever Excel creates a new workbook. Note that it will only be called if event-sinking is switched on 
            (using CXllApp::SetSinkEvents()). You can override the method in your application class
            to react to the event.
            The default method checks for a function which has been registered as a
            callback for this event 
            using CXllApp::SetComEventHandler(),
            and calls it if it is present.
You should only implement this function if you need access to Excel's COM interfaces.
			If you just want to call an add-in function, use the much simpler mechanism 
			provided by CXllApp::SetComEventHandler().
			
Header: xllplus.h
CXllApp Class 
					  | CXllApp Methods			 
					  | CXllApp::OnWorkbookOpen()			 
					  | CXllApp::GetSinkEvents()			 
					  | CXllApp::SetSinkEvents()