add progress bar to status bar

It can be used to display progress during program upload.
To use it call ShowPLCProgress (like ShowPLCProgress("transfered",
10)) in your PLCObject implementation.

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot xmlns:xsd="http://www.w3.org/2001/XMLSchema" URI_location="LOCAL://">
  <TargetType>
    <Linux/>
  </TargetType>
</BeremizRoot>