Add possibility to change the test message box title in dialog sample.

All the other message box elements were configurable, so why not this one.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71213 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dialogs/dialogs.h

@@ -208,6 +208,7 @@ public:
     bool Create();
 
 protected:
+    wxString GetTitle() { return m_textTitle->GetValue(); }
     wxString GetMessage() { return m_textMsg->GetValue(); }
     long GetStyle();
 
@@ -251,7 +252,8 @@ private:
         MsgDlgIcon_Max
     };
 
-    wxTextCtrl *m_textMsg,
+    wxTextCtrl *m_textTitle,
+               *m_textMsg,
                *m_textExtMsg;
 
     wxCheckBox *m_buttons[Btn_Max];