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>

Beremiz's user manual
=====================

Contents:

.. toctree::
   :maxdepth: 2

   install
   start
   edit
   build
   connectors
   debug