Added wxInfoBar::AddButton().

Allow adding custom buttons to wxInfoBar and show this in the sample.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62270 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/infobar.h

@@ -40,6 +40,8 @@ public:
 
     virtual void ShowMessage(const wxString& msg, int flags = wxICON_NONE);
 
+    virtual void AddButton(wxWindowID btnid, const wxString& label = wxString());
+
 
     // methods specific to this version
     // --------------------------------