Extracted reusable method in PipingFailureMechanismContextProperties. Improved documentation in IFailureMechanismPropertyChangeHandler. Added test cases for FailureMechanismPropertyChangeHandlerTest and GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandlerTest. outlining Related to Issue [WTI-967] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@7631 5a3db67b-de53-47b5-99c8-a1c30a6650e2