Add "Generate Program" to toolbar in PLCOpenEditor standalone mode.

Currently you can find the "Generate Program" action only in the file menu,
but this action is very often used in standalone mode, so I added toolbuffon.

<?xml version='1.0' encoding='utf-8'?>
<BaseParams xmlns:xsd="http://www.w3.org/2001/XMLSchema" IEC_Channel="0" Name="py_ext_0"/>