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.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
  <Libraries Enable_Python_Library="true"/>
</BeremizRoot>