Python2 and Python3.

    - Pinocchio is now fully operational for the polytope operations.
    - Modify RobotSolver into a structure similar to URDFSolver; now, KDL and
    Pinocchio can be used in order to manage the .urdf model according to the
    choices of the user.

    - Add compatibility with Python 3
    - Add a more generic interface for URDF files (urdf_[...].py instead of panda_[...].py).
    - Begin the implementation of Pinocchio

    Drawbacks to the use of Python 3 :
    - ROS and Pinocchio should be compatible with Python3
    - PyKDL should be installed from source (please check Readme.md).

Update .gitlab-ci.yml

See merge request askuric/polytope_vertex_search!1