Added context menu for HydraulicBoundary. Implemented file selection. Related to Issue [WTI-326]git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@2084 5a3db67b-de53-47b5-99c8-a1c30a6650e2Former-commit-id: 710e7e8b23a9799a7b91defc9f883928bbf53979Former-commit-id: 3e4de0a25e948ea7c157ee6fd600458710647409