Tuto

Few fix on tutorials.

But a last bug is remaining : I can't test the notebooks in examples dir, because the jupyter lab (or notebook) installation impose new version of importlib_metadata and jsonschema, which are for the moment incompatible with the dnadna setup.

  - importlib_metadata                 1.5.0  py38_0          conda-forge     Cached
  + importlib_metadata                 6.8.0  hd8ed1ab_0      conda-forge        9kB
  - jsonschema                         4.6.2  pyhd8ed1ab_0    conda-forge     Cached
  + jsonschema                        4.19.1  pyhd8ed1ab_0    conda-forge       71kB