Fixes

* set correct time zone
* use RVO (MS review refs #561)

src/blackmisc/datastore.cpp

@@ -46,8 +46,7 @@ namespace BlackMisc
     QJsonValue IDatastoreObjectWithIntegerKey::getDbKeyAsJsonValue() const
     {
         if (this->hasValidDbKey()) { return QJsonValue(this->m_dbKey); }
-        static const QJsonValue null;
-        return null;
+        return QJsonValue();
     }
 
     void IDatastoreObjectWithIntegerKey::setKeyAndTimestampFromDatabaseJson(const QJsonObject &json, const QString &prefix)

src/blackmisc/datastoreutility.cpp

@@ -13,6 +13,7 @@
 #include "blackmisc/stringutils.h"
 #include <QJsonObject>
 #include <QJsonDocument>
+#include <QTimeZone>
 
 using namespace BlackMisc;
 using namespace BlackMisc::Simulation;
@@ -56,6 +57,7 @@ namespace BlackMisc
         {
             QString ts(timestamp.trimmed().remove(' ').remove('-').remove(':')); // normalize
             QDateTime dt = QDateTime::fromString(ts, "yyyyMMddHHmmss");
+            dt.setTimeZone(QTimeZone::utc());
             return dt;
         }
         else