AHaumer: parameter default VKnee=0 for Electrical.Analog.Ideal.7IdealDiode, IdealThyristor, IdealGTOThristor0

git-svn-id: https://svn.modelica.org/projects/Modelica/branches/maintenance/3.2.1@7281 7ce873d0-865f-4ce7-a662-4bb36ea78beb