Fixed systematically loading PLC binary at startup even without -a parameter. Extended py_ext extensions instances variable description (PLCGlobalsDesc). Now contains list of variables organizd by extension, with extension name

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