Investigate changes to the core computational loop

[marcharper]

Now that all strategies can be pickled, we may be able to simplify the match generating code and the batch processing of matches. This may also improve the efficiency of tournaments.

[drvinceknight]

Good idea! Something that could help/enhance is using dask for the parallelisation which would clean things up nicely and also allow for the use of any dask scheduler (including distributed ones).