5af64cc7 remove CleanCommand to keep setup.py simpler

examples/cython/c_interface/setup.py

examples/cython/c_interface_shared_object/setup.py

examples/cython/c_numpy/setup.py

examples/pybind11/setup.py

examples/pybind11/src/cube.cpp

examples/pybind11/src/pybex.cpp

notebooks/2e--Interfacing_with_C_and_F.ipynb