Piping Failure mechanism can only be added if no piping failure mechanism is assigned to the wti project. Calling remove on presenters which do not support it will now throw InvalidOperation exceptions. Moved Initialize and Clear logic of PipingFailureMechanism on WtiProject to WtiProject. Related to Issue [WTI-13] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@272 5a3db67b-de53-47b5-99c8-a1c30a6650e2