Added validation to IllustrationPointsParser where double values can be DBNull Related to Issue [WTI-1303]git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@10432 5a3db67b-de53-47b5-99c8-a1c30a6650e2Former-commit-id: 97c5cdb8e50fced507025066390a959a1681fa21Former-commit-id: 509f6edbe1e6029345536e8a4a8212f8c1bca679