Icepool

* Fixed weighting bug in `__matmul__` when the left die has an outcome of 0.
* Retired the names `standard` and `bernoulli`. These will be just `d` and `coin` respectively.
* `apply` now accepts `Pool` arguments, which will have `expand()` called on them.
* Reinstate automatic Cartesian product in `Population` construction.
* `if_else` now runs in two stages.

* Incremental sorting for `all_matching_sets` to reduce state space.
* `lowest()` and `highest()` now actually visible.
* Improved checking for tuple outcome sortability and types.

Prepend `sum_` to OutcomeCountGenerator versions of `highest` and `lowest`.

Expanded typing, particularly in terms of parameterizing types.

* `Die` and `Deck` constructors now expect exactly one nesting level, e.g. a Sequence of outcomes.
* Removed `Die.bool()`.
* `**kwargs` replaced with explcit `again_depth`, `again_end`. Removed `OutcomeCountEvaluator.final_kwargs()`.
* Split `include_steps` version of `Die.map()` into a `map_and_time` method.
* Split `include_outcome` version of `best_matching_set` and `best_straight` into separate methods.
* Rename `keep_highest` and `highest` to `sum_highest`; add just `highest` for taking the single highest.
* Same for `lowest`.
* Added `cartesian_product()`, took this functionality out of the `Die` constructor for now.
* Added `OutcomeCountGenerator.all_matching_sets()`.

* `Die.sub()` renamed to `Die.map()`.
* `Die.map()` can now include the number of steps taken until absorption.
* `Die.reroll_until()` renamed to `Die.filter()`.
* `wilds` arguments marked experimental, pending decision on how ordering should affect them.
* Only tuples get separate columns in tables and not `str` or `bytes`.
* Non-recursive algorithm for `Again()` handling.

* Nested lists are now allowed in the `Die()` constructor.
* Single outcomes can be sent to the `Die()` constructor without wrapping them in a list.
* Same for sending a die to the `Pool()` constructor.
* Add `Die.probabilities_lt()`, `Die.probabilities_gt()` methods.
* Add `wilds` argument to `contains_subset()` and `intersection_size()` methods.
* Removed `extra_dice` argument from `Die.sub()`.
* Added `sub()` method to `Deck`, though with less features than the `Die` version.
* `sum()` method of generators now has a `sub` option that maps outcomes before summing.
* `expand()` method of generators now has a `unique` option that counts duplicates only once.
* Forwarding of `kwargs` to `Die()` replaced with explicit arguments.
* Add comparators to `Again`.
* Experimental absorbing Markov chain analysis for `Die.sub(depth=None)`.