- Changed all boxmodels to parameter file: no other argument required

- Everything and the kitchen sink can be specified in there. Example:
  the 2p2c test
- Minor changes to the parameter file syntax: parameters do not start
  with capital any more
- It is checked now whether the parameter file exists
- How to use the program / parameter file can be queried by ./progName
  --help
- Documentation: /dumux/common/start.hh and the parameterfiles themselves


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@7607 2fb0f335-1f38-0410-981e-8018bf24f1b0