Added placeholders for Piping calculations in the interface. Added PipingDataNodeController to add interactions between the calculation and the PipingDataNodePresenter. Added context menu for a pipingData node which contains the item to start a calculation. Related to Issue [WTI-13] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@75 5a3db67b-de53-47b5-99c8-a1c30a6650e2