* Extracted extension methods for IDistribution that were commonly used in *CalculationConfigurationImporter classes ** Fixed inconsistencies between Piping and GrassCoverErosionInwards variants. * Renamed test files to prevent 'valid*invalid' naming pattern, solving ambiguity on what 'valid' means Related to Issue [WTI-1155] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@8983 5a3db67b-de53-47b5-99c8-a1c30a6650e2