added wxBU_NOTEXT style to allow creating bitmap buttons with stock id not showing the label, as it was possible before

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61104 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/bmpbuttn.h

@@ -41,7 +41,8 @@ public:
                 const wxString& name = wxButtonNameStr)
     {
         if ( !wxBitmapButtonBase::Create(parent, id, "",
-                                         pos, size, style,
+                                         pos, size,
+                                         style | wxBU_NOTEXT,
                                          validator, name) )
             return false;