Move illustration points property up a level, removing an unnecessary level in the tree. Related to Issue [WTI-1310]git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@10922 5a3db67b-de53-47b5-99c8-a1c30a6650e2Former-commit-id: 90605f2bd430ebaf18819f9c285b33bd21fa36e6Former-commit-id: a880c4a2ac68bab6eac6fba5af0f3e42ebd01de6