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* In ABCSMC.run, allow a default infinite number of iterations, and log the
ESS in each iteration.
* Reformulate exponential temperature decay, allowing for a fixed number of
iterations or fixed ratios.
* Solve acceptance rate temperature match in log space for numeric stability.
* Perform temperation of likelihood ratio in log space for numeric stability
(all 221).
* Fix wrong maximum density value in binomial kernel.
* Allow not fixing the final temperature to 1 (all 223).
* Allow passing id to history directly (225).
* Pass additional arguments to Acceptor.update.
* Give optional min_rate argument to AcceptanceRateScheme (all 226).
* In plot functions, add parameter specifying the reference value color (227).