Added exception message for scenario where beta values are not present. Removed filter on PeriodId for GeneralBetaValues and GeneralAlphaValues and added the filter to governingWindDirection determination. Related to Issue [WTI-1302] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@10551 5a3db67b-de53-47b5-99c8-a1c30a6650e2