test(z): fix DTG namespace usage; tidy CMake mismatches

Z/src/ngltools/tests/NGLToolsQtSmokeTest.cpp

@@ -11,10 +11,10 @@ private slots:
     void testDTG()
     {
         QDateTime now = QDateTime::currentDateTimeUtc();
-        QString s = NGL::toString(now);
+        QString s = DTG::toString(now);
         QVERIFY(!s.isEmpty());
         bool ok = false;
-        QDateTime parsed = NGL::fromDTGString(s, &ok);
+        QDateTime parsed = DTG::fromDTGString(s, &ok);
         QVERIFY(ok);
         QVERIFY(parsed.isValid());
     }