-moving the property to NumericalModel
-removing it from implicit properties and ~defaults
-moving query from implicitproblem.hh to the same method in timeManager.hh
reviewed by Klaus

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@10110 2fb0f335-1f38-0410-981e-8018bf24f1b0