added wxBookCtrl::ChangeSelection() which is the same as SetSelection() but doesn't send the page change events (second part of patch 1553551)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41738 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/cocoa/notebook.h

@@ -62,6 +62,9 @@ public:
     // get the currently selected page
     int GetSelection() const;
 
+    // changes selected page without sending events
+    int ChangeSelection(size_t nPage);
+
     // set/get the title of a page
     bool SetPageText(size_t nPage, const wxString& strText);
     wxString GetPageText(size_t nPage) const;