Upgrade to version 1.6.5

[BDonnot]

This release focuses on grid2op improvment, especially adressing some enhancement of the github issues.

Breaking changes

• the function "env.reset()" now reset the underlying pseudo random number generators
  of all the environment subclasses (eg. observation space, action space, etc.) This change has been made to
  ensure reproducibility between episodes: if env.seed(...) is called once, then regardless of what happens
  (basically the number of "env.step()" between calls to "env.reset()")
  the "env.reset()" will be generated with the same prng (drawn from the environment)
  This effect the opponent and the chronics (when maintenance are generated "on the fly").
• the name of the python files for the "Chronics" module are now lowercase (complient with PEP). If you
  did things like from grid2op.Chronics.ChangeNothing import ChangeNothing you need to change it like
  from grid2op.Chronics.changeNothing import ChangeNothing or even better, and this is the preferred way to include
  them: from grid2op.Chronics import ChangeNothing. It should not affect lots of code (more refactoring of the kind
  are to be expected in following versions).
• same as above for the "Observation" module. It should not affect lots of code (more refactoring of the kind
  are to be expected in following versions).

Fixed issues

• a bug for the EpisodeData that did not save the first observation when
  "add_detailed_output" was set to True and the data were not saved on disk.
• an issue when copying the environment with the opponent (see issue Opponent seed is not propagated after env.copy() #274)
• a bug leading to the wrong "backend.get_action_to_set()" when there were storage units on the grid.
• a bug in the "BackendConverter" when there are storage on the grid
• issue There may be an error in 03_Action.ipynb #265
• issue AttributeError: Can't get attribute 'CompleteAction..."env_name"' => update the example notebook #261

New features

• possibility to "env.set_id" by giving only the folder of the chronics and not the whole path.
• function "env.chronics_handler.available_chronics()" to return the list of available chronics
  for a given environment
• possibility, through the Parameters class, to limit the number of possible calls to obs.simulate(...)
  see param.MAX_SIMULATE_PER_STEP and param.MAX_SIMULATE_PER_EPISODE (see issue Count the number of use of "simulate" per step and globally #273)
• a class to generate a "Chronics" readable by grid2op from numpy arrays (see Add a possibility to load chronics from a numpy array #271)
• an attribute delta_time in the observation that tells the time (in minutes) between two consecutive steps.
• a method of the action space to show a list of actions to get back to the original topology
  (see Create a "get back to meshed topology"  #275)
  env.action_space.get_back_to_ref_state(obs)
• a method of the action to store it in a grid2op independant fashion (using json and dictionaries), see act.as_serializable_dict()
• possibility to generate a gym DiscreteActSpace from a given list of actions (see Discrete gym act space with given list of actions #277)
• a class that output a noisy observation to the agent (see NoisyObservation): the agent sees
  the real values of the environment with some noise, this could used to model inacurate
  sensors.

Improvements

• observation now raises Grid2OpException instead of RuntimeError
• docs (and notebooks) for the "split_train_val" In the notebook, explain the train / val / test split #269
• the "split_train_val" function to also generate a test dataset see Improve split train / val / test #276