* 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
In #85 the voice context will be renamed to audio context, so the CValueObject classes will be renamed to namespace Audio too.
As #140 changes many CValueClasses, this crossover change is done in the same unit of work.