Merge branch 'freeflow/cleanup' into 'master'

dumux/common/parameters.hh

dumux/discretization/staggered/freeflow/fickslaw.hh

dumux/discretization/staggered/freeflow/maxwellstefanslaw.hh

dumux/freeflow/navierstokes/volumevariables.hh

dumux/freeflow/navierstokesnc/indices.hh

dumux/freeflow/navierstokesnc/staggered/fluxvariables.hh

dumux/freeflow/navierstokesnc/staggered/localresidual.hh

dumux/freeflow/navierstokesnc/volumevariables.hh

dumux/freeflow/navierstokesnc/vtkoutputfields.hh

dumux/freeflow/rans/problem.hh

dumux/freeflow/rans/volumevariables.hh

dumux/freeflow/rans/zeroeq/problem.hh

dumux/freeflow/rans/zeroeq/volumevariables.hh

dumux/freeflow/ransnc/volumevariables.hh

dumux/material/binarycoefficients/h2o_ch4.hh

dumux/material/binarycoefficients/h2o_constant.hh

test/freeflow/navierstokesnc/msfreeflowtestproblem.hh

test/freeflow/ransnc/CMakeLists.txt

test/freeflow/ransnc/channeltestproblem.hh

test/freeflow/ransnc/test_channel_zeroeq2c.input