better interface to get binary certificates; refs #28

doc/examples/suisse-id-demo.cxx

@@ -80,8 +80,8 @@ int main(int argc, char** argv) try {
         } else if (choice=="z") {
           for (suisseid::Certificates::iterator cert(certs.begin());
                cert!=certs.end(); ++cert) {
-            QByteArray der(QByteArray(cert->data(), cert->size()));
-            QSslCertificate c(der, QSsl::Der);
+            QSslCertificate c(QByteArray(cert->data(), cert->size()),
+                              QSsl::Der);
             std::cout<<"Certificate info: CN="
                      <<QString(c.subjectInfo(QSslCertificate::CommonName)
                                .toUtf8()).toStdString()