GitLab

made the env loading more forgiving (in persistence) to allow the loading of old envs, and msgpack files with .pkl extension.  Also give default 100 max_episode_steps where this is missing.  Add test-saved-envs notebook to test loading all old envs.

Reintroduced some malfunction parameters but are not used.

Also updated the way we handle task generation for sparse rail generator

updated docstrings for multiple functions in distance_map.pz, transition_map.py and schedule_generators.py

add named tuple for result of schedule generator and add max_episode_steps to the schedule generator