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
<xsd:attribute name="Compiler" type="xsd:string" use="optional" default="gcc"/>
<xsd:attribute name="CFLAGS" type="xsd:string" use="required"/>
<xsd:attribute name="Linker" type="xsd:string" use="optional" default="gcc"/>
<xsd:attribute name="LDFLAGS" type="xsd:string" use="required"/>