Merge branch 'feature/chemical-nonequilibrium-2p2c' into 'master'

dumux/porousmediumflow/2p2c/model.hh

dumux/porousmediumflow/2p2c/volumevariables.hh

dumux/porousmediumflow/2pnc/model.hh

dumux/porousmediumflow/nonequilibrium/iofields.hh

dumux/porousmediumflow/nonequilibrium/localresidual.hh

dumux/porousmediumflow/nonequilibrium/model.hh

.../porousmediumflow/nonequilibrium/thermal/localresidual.hh

dumux/porousmediumflow/nonequilibrium/volumevariables.hh

dumux/porousmediumflow/nonisothermal/localresidual.hh

test/porousmediumflow/2p2c/implicit/CMakeLists.txt

...mflow/2p2c/implicit/chemicalnonequilibrium/CMakeLists.txt

...usmediumflow/2p2c/implicit/chemicalnonequilibrium/main.cc

...iumflow/2p2c/implicit/chemicalnonequilibrium/params.input

...ediumflow/2p2c/implicit/chemicalnonequilibrium/problem.hh

...low/2p2c/implicit/chemicalnonequilibrium/spatialparams.hh

test/references/test_2p2c_nonequilibrium_box-reference.vtu

test/references/test_2p2c_nonequilibrium_tpfa-reference.vtu