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.

                  <xsd:element name="Linux">
                    <xsd:complexType>
                      %(toolchain_gcc)s
                    </xsd:complexType>
                  </xsd:element>