Connected IStructureUpdateStrategy in the StabilityPointStructuresImporter: - Promoted IStructureUpdateStrategy constructor argument to the base class for all the importers - Changed tests, removed obsolete test for the stability point structures importer that assures the uniqueness of stability point structure items after the import action. Test can be removed because the import target is of type ObservableUniqueItemCollectionWithSourcePath Related to Issue [WTI-1184] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@10071 5a3db67b-de53-47b5-99c8-a1c30a6650e2