Icepool

* `map` and similar functions will attempt to guess `star`.
* Changed `positive_only` parameter to `expression.all_counts` to `filter`.
* Changed implementation of bound generators to unbind expressions rather than dynamically splitting.
* Retired `apply_sorted` and variants.
* Add `outcome_function` decorator similar to `apply`.
* Add `map_counts` expression.
* `Reroll` in tuple outcomes and joint evaluations causes the whole thing to be rerolled.

* Tuple outcomes can now be compared with single outcomes.
* Add `.keep, .highest, lowest, .middle` variants of `apply_sorted`.
* Recommend `multiset_function` be used as a decorator, add `update_wrapper`.
* Add `keep_outcomes, drop_outcomes` methods to expressions.
* Add `any` evaluation to expresions.

Comparisons on dice with tuple outcomes are now performed elementwise.

Testing GitHub workflows.

Expanded multiset processing with multiset expressions.

* `OutcomeCountGenerator`, `OutcomeCountEvaluator` renamed to `MultisetGenerator`, `MultisetEvaluator`.
* `multiset_function` is an easy way to create joint evaluators.
* `Pool` indexing is now relative rather than absolute.
* Renamed `pool.sorted_roll_counts` to `pool.keep` and `pool.keep_tuple`.
* `Die` versions of `sum_highest` etc. renamed to just `highest`; these always return dice.
* `MultisetExpression` (including generators like `Pool`) have `highest()` returning an expression.
* `Die` operators now does mixed vector-scalar binary operations by broadcasting the scalar.
* Add `middle()` methods.
* Remove `*generators` argument from `evaluator.order()`, `evaluator.final_outcome()`.
* `*generators` argument of `evaluator.alignment` replaced with the union of all generator outcomes.
* Removed suits.
* Stop using `__class_getitem__`, which is intended for typing only.

Reworked built-in generators and evaluators.

* Generators now support multiset operations. These include:
* Multiset comparisons (`<, <=, >, >=, ==, !=, isdisjoint`), which produce `Die[bool]`.
* Multiset operators (`+`, `-`, `|`, `&`, `^`) which produce wrapped generators.
* A suite of chainable count adjustments, including `multiply_counts`, `divide_counts`, `filter_counts`, and `unique`.
* Rename `median_left` to `median_low` etc.
* Generators and evaluators are now paramterized by count type as well.
* Move concrete evaluators to a submodule.