refs #314, fromQVariant / location of toQVariant

* renamed fromQVariant to convertFromQVariant, the "from" methods imply the object is changed (fromJson, fromString ..)
* implemented fromQVariant - changing the object by QVariant
* moved toQVariant into PQ template
* free function setFromQVariant

src/blackmisc/dictionary.h

@@ -207,9 +207,12 @@ namespace BlackMisc
             removeByValueIf(BlackMisc::Predicates::MemberEqual(membFunc, returnValue));
         }
 
-        //! \copydoc BlackMisc::CValueObject::toQVariant
+        //! \copydoc CValueObject::toQVariant()
         virtual QVariant toQVariant() const override { return QVariant::fromValue(*this); }
 
+        //! \copydoc CValueObject::fromQVariant
+        virtual void fromQVariant(const QVariant &variant) override { BlackMisc::setFromQVariant(this, variant); }
+
         //! \copydoc BlackMisc::CValueObject::getValueHash
         virtual uint getValueHash() const override { return qHash(this); }