Removed unused AbovePhreaticLevel and DryUnitWeight properties from readers and storing classes. Removed unused EffectiveStress property from the IEffectiveThicknessCalculator and implementors. Due to stochastic parameters, effective stress needs to be calculated in Ringtoets. Related to Issue [WTI-686] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@4135 5a3db67b-de53-47b5-99c8-a1c30a6650e2