Add window icon.

src/main.cpp

@@ -31,6 +31,7 @@ int main(int argc, char *argv[]) {
   app.setOrganizationName("ENCOM");
   app.setOrganizationDomain("encom.eu.org");
   app.setApplicationName("Spectral");
+  app.setWindowIcon(QIcon(":/assets/img/icon.png"));
 
   app.setQuitOnLastWindowClosed(false);