- all boxmodels start with paremeter files now

- each model specifies in the *.cc file which parameters are mandatory
- syntax as well as output further homogenized and beautified
- for seeing how to group entries in the input file and how to use them
  in the problem: please have a look at test_2p2c
- for seeing how to create your own grid (no dgf): please have a look at
  test_2pni
- for specifying a lense:  please have a look at test_2p



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@7672 2fb0f335-1f38-0410-981e-8018bf24f1b0