Moved piping calculation related classes to subdirectories in Wti.Calculation. Created a minimal implementation of PipingSurfaceLineCreator and PipingProfileCreator which should create PipingSurfaceLine and PipingProfile when they can be obtained from the data model. Added the EffectiveThicknessCalculator to the calculation for piping. - EffectiveStress is now taken from the result of the EffectiveThicknessCalculator. Related to Issue [WTI-8] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@56 5a3db67b-de53-47b5-99c8-a1c30a6650e2