Added exception handling for unknown columns IDataReaderExtensions. Added test for the base implementation of CopyMetaDataIntoFeature, which should correctly read null values. Related to Issue [WTI-948] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@6541 5a3db67b-de53-47b5-99c8-a1c30a6650e2