python: use pathlib

demo/demo_quadruped.py

demo/demo_tsid_talos_gripper_closed_kinematic_chain.py

exercizes/ex_4_conf.py

exercizes/ex_4_long_conf.py

exercizes/ex_4_talos_conf.py

...zes/notebooks/ex_0_joint_space_inverse_dynamics_arm.ipynb

exercizes/notebooks/ex_1_com_sin_track_talos.ipynb

exercizes/romeo_conf.py

exercizes/talos_arm_conf.py

exercizes/talos_conf.py

exercizes/ur5_conf.py

exercizes/ur5_reaching_conf.py

tests/python/test_Contact.py

tests/python/test_ContactPoint.py

tests/python/test_Formulation.py

tests/python/test_Gravity.py

tests/python/test_RobotWrapper.py

tests/python/test_Tasks.py