SVGHMI: finally found why HMI:Input wasnt't initializing properly: vsprintf takes a list. Also, removed intermediate variable last_val, since edit_value() works on strings anyhow, and in case of formated floats, it is better to workl on already formated value.

                  <xsd:element name="Win32">
                    <xsd:complexType>
                      %(toolchain_gcc)s
                    </xsd:complexType>
                  </xsd:element>