Add 256x256 and 64x64 Beremiz icons


remove svg:midPointStop tags from icons.svg, because Inkscape
complained about unsupported tag. It seems that these tags were made
by Adobe Illustrator and aren't supported by any other app.

.. Beremiz documentation master file

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

Contents:

.. toctree::
   :maxdepth: 2

   overview
   manual/index
   standards