Replacing Alberto's orbits module by Girodana's one

...ore/sempy/core/orbits/__pycache__/__init__.cpython-38.pyc

...e/sempy/core/orbits/__pycache__/crtbporbit.cpython-38.pyc

sempy_core/sempy/core/orbits/__pycache__/halo.cpython-38.pyc

sempy_core/sempy/core/orbits/__pycache__/nrho.cpython-38.pyc

...y_core/sempy/core/orbits/__pycache__/orbit.cpython-38.pyc

...y_core/sempy/core/orbits/__pycache__/plyap.cpython-38.pyc

...y/core/orbits/__pycache__/thirdorder_orbit.cpython-38.pyc

sempy_core/sempy/core/orbits/butterfly.py

sempy_core/sempy/core/orbits/crtbporbit.py

sempy_core/sempy/core/orbits/dro.py

sempy_core/sempy/core/orbits/halo.py

sempy_core/sempy/core/orbits/nrho.py

sempy_core/sempy/core/orbits/plyap.py

...mpy/core/orbits/tests/__pycache__/__init__.cpython-38.pyc

...mpy/core/orbits/tests/__pycache__/test_dro.cpython-38.pyc

...its/tests/__pycache__/test_manifold_branch.cpython-38.pyc

...its/tests/__pycache__/test_nrho_validation.cpython-38.pyc

...y/core/orbits/tests/__pycache__/test_orbit.cpython-38.pyc

...bits/tests/__pycache__/test_orbit_sampling.cpython-38.pyc

...ts/tests/__pycache__/test_orbit_validation.cpython-38.pyc