enable payoff matrix to process simultaneous actions, adapt GM, add example

[antoniogois]

Problem

Currently it is not possible to use the PayoffMatrix component to model simultaneous-move games (e.g. Prisoner’s Dilemma), since this component does not support players that act in parallel. (PayoffMatrix requires EventResolution, which in turn calls get_currently_active_player(), which is incompatible with the Simultaneous engine)

When using the Sequential engine, PlayerB observes whether PlayerA cooperated before it has to choose its action, changing the nature of the game.

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Solution

This pull request adds explicit support for simultaneous actions with PayoffMatrix:

• Implements a new component NextActingAllEntitiesFromSceneSpec
• Main change: Provides PayoffMatrix with a new parameter acting_order . Default behaviour remains unchanged, but if set to simultaneous it processes multiple actions in the same round (without calling EventResolution)
• Adapt game_theoretic_and_dramaturgic game master to have a new parameter acting_order. Use parallel actions if acting_order== simultaneous.
• Add new notebook with example usage examples/iterated_prisoners_dilemma.ipynb

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