logo: modified the logo so it looks better when used as mainicon for the gui program

gui/main.cpp

@@ -24,7 +24,7 @@
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
-    app.setWindowIcon(QIcon("../logo.svg"));
+    app.setWindowIcon(QIcon("../logo.png"));
 
     MainWindow window;
     window.show();