[1pnc] clean up and add cc-testproblem

dumux/porousmediumflow/1pnc/implicit/model.hh

dumux/porousmediumflow/1pnc/implicit/newtoncontroller.hh

dumux/porousmediumflow/1pnc/implicit/propertydefaults.hh

dumux/porousmediumflow/1pnc/implicit/volumevariables.hh

test/porousmediumflow/1pnc/implicit/1pnctestproblem.hh

test/porousmediumflow/1pnc/implicit/1pnctestspatialparams.hh

test/porousmediumflow/1pnc/implicit/CMakeLists.txt

test/porousmediumflow/1pnc/implicit/test_box1pnc.cc

test/porousmediumflow/1pnc/implicit/test_box1pnc.input

test/porousmediumflow/1pnc/implicit/test_cc1pnc.cc

test/porousmediumflow/1pnc/implicit/test_cc1pnc.input