adaptive methods mapping the solution to the new grid now pass the element...

adaptive methods mapping the solution to the new grid now pass the element instead of the problem (because the cell volume is required to map volume-depenedent primary variables such as total concentration). This has no influence in stable because both arguments are only used by compositional adaptive models.
okayed by Markus

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@8855 2fb0f335-1f38-0410-981e-8018bf24f1b0