Enhanced playstyle and game tools

Many additions and changes compared to the previous release v2.1.1:

• added cooldown on actions and on topological elements (lines, substations)
• added limit on the number of topological elements actionable per turn
• added further baseline agents
• added csv saving of logs
• added handling of IEEE format for input grids
• added various tools to obtain information from the environment or check the validity of actions
• improved the renderer
• improved command line arguments
• improved and enhances documentation https://pypownet.readthedocs.io/en/latest/
• various bugfixes
• added unit and contextual tests; thanks @ZergD
• pypownet is now on PyPi!

Furthermore, environments are now of type Gym environments, thus facilitating the use of reinforcement learning approaches and baselines.

v2.1.1

Merge branch 'master' of https://github.com/MarvinLer/pypownet