various fixes, comments\n load_xml file was moved to Trace.cpp in order to separate this from the node selection interface => Now node selection work with SVG, and -e flag can be used with -c flag. \n Use of QCoreApplication instead of QApplication when we don't need an interface (-e flag for the moment, but will also be useful when -s flag will be added to split the trace) => ViTE now works without the need of an X server for svg export\n