xmlreader/xmlinputdata: making fields protected and properties virtual

...ation/DataProvider/XMLAuxiliaryDeclarationDataProvider.cs

...eclaration/DataProvider/XMLDeclarationADASDataProvider.cs

...aration/DataProvider/XMLDeclarationAirdragDataProvider.cs

...tion/DataProvider/XMLDeclarationAngledriveDataProvider.cs

...ion/DataProvider/XMLDeclarationAuxiliariesDataProvider.cs

...eclaration/DataProvider/XMLDeclarationAxleDataProvider.cs

...ration/DataProvider/XMLDeclarationAxlegearDataProvider.cs

...claration/DataProvider/XMLDeclarationAxlesDataProvider.cs

...tion/DataProvider/XMLDeclarationComponentsDataProvider.cs

...laration/DataProvider/XMLDeclarationEngineDataProvider.cs

...aration/DataProvider/XMLDeclarationGearboxDataProvider.cs

...claration/DataProvider/XMLDeclarationInputDataProvider.cs

...ration/DataProvider/XMLDeclarationJobInputDataProvider.cs

...ration/DataProvider/XMLDeclarationRetarderDataProvider.cs

...DataProvider/XMLDeclarationTorqueConverterDataProvider.cs

...eclaration/DataProvider/XMLDeclarationTyreDataProvider.cs

...aration/DataProvider/XMLDeclarationVehicleDataProvider.cs

...utData/FileIO/XML/Declaration/DataProvider/XMLGearData.cs

...tData/FileIO/XML/Declaration/Reader/Impl/XMLADASReader.cs

.../FileIO/XML/Declaration/Reader/Impl/XMLComponentReader.cs