- added asserts for the mass/mole formulations in the coupling
  conditions to ensure that the coupling conditions are applied
correctly
- skip test in case SuperLU or UMFPack are not available
- updated documention and use of properties

reviewed by gruenich



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@15055 2fb0f335-1f38-0410-981e-8018bf24f1b0