added wxTextCtrl::ChangeValue() which is the same as SetValue() but doesn't send the text changed event (first part of patch 1553551)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41739 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/text/text.cpp

@@ -947,7 +947,7 @@ void MyTextCtrl::OnKeyDown(wxKeyEvent& event)
         case WXK_F6:
             wxLogMessage(_T("IsModified() before SetValue(): %d"),
                          IsModified());
-            SetValue(_T("SetValue() has been called"));
+            ChangeValue(_T("ChangeValue() has been called"));
             wxLogMessage(_T("IsModified() after SetValue(): %d"),
                          IsModified());
             break;