Runtime/PLCObject : move call to PreStartPLC right after call to the "start" method of all python extensions, and then just before the start of the python loop executing python_* blocks.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="LOCAL://">
  <TargetType/>
</BeremizRoot>