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-a1c30a6650e2Former-commit-id: 6def9369dc68d3d803284d9eda2071d9f2d98ab3Former-commit-id: 815b581fbe601d6453809fcc5b22e2ca4a46e32e