make run Beremiz and PLCOpen Editor, if full path contain non-lating
characters

There was a problem in About dialog and in project properites tab and
probably in my other places, when str is automatically converted to
unicode string using ascii.
This patch converts str to unicode using proper encoding at the very beggining.

.. Beremiz documentation master file

Beremiz's documentation
=======================

Contents:

.. toctree::
   :maxdepth: 2

   overview
   manual/index
   standards