Merged in masterschlumpf/beremiz/wx3-fix (pull request #37)

Fix an exception with wx-3.0-gtk3 in PLCOpenEditor when generating ST files

Approved-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>

<?xml version="1.0" encoding="UTF-8"?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
</BeremizRoot>