implicit branch: start adapting CMake/CTest. Use the correct names for the box tests. Move reference solutions to a separate directory. Build cell centered tests (do not actually test them yet).

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/branches/implicit@9793 2fb0f335-1f38-0410-981e-8018bf24f1b0