Listools

Four new functions:

* `listutils.period_len(input_list[, ignore_partial_cycles])`
* `listutils.scrambled(input_list)`
* `llogic.is_ascending(input_list[, step])`
* `llogic.is_descending(input_list[, step])`

Changelog:

* improvements to the documentation

Changelog:

* added Sphinx autodoc

Changelog:

* `listutils.list_mask(input_list, mask)`: doesn't cycle the `mask` when it is shorter than `input_list`.
* `listutils.list_mask_cycle(input_list, mask)`: cycles the `mask` when it is shorter than `input_list` (same behaviour as `listutils.list_mask` in version 2.0.2)

* `flatools.flatten_index(element, input_list)`
* `flatools.flatten_join(*input_lists)`
* `flatools.flatten_len(input_list)`
* `flatools.flatten_max(input_list, *[, key, default])`
* `flatools.flatten_min(input_list, *[, key, default])`
* `flatools.flatten_mixed_type(input_list)`
* `flatools.flatten_reverse(input_list)`
* `flatools.flatten_single_type(input_list)`
* `flatools.flatten_sorted(input_list, *[, key, reverse])`
* `flatools.flatten_sum(input_list[, start])`
* `flatools.flatten_zip_cycle(*input_lists)`
* `flatools.flatten(input_list)`
* `flatools.pflatten(input_list[, depth])`

* `iterz.cycle_until_index(input_iter, i)`
* `iterz.inf_cycle(input_iter)`
* `iterz.iter_mask(input_iter, mask)`
* `iterz.ncycles(input_iter, n)`
* `iterz.zip_cycle(*input_iters)`
* `iterz.zip_inf_cycle(*input_iters)`
* `iterz.zip_longest(*input_iters[, default])`
* `iterz.zip_syzygy(*input_iters)`

* `listutils.list_lcm(input_list)`
* `listutils.list_mask(input_list, mask)`
* `listutils.list_gcd(input_list)`

* `llogic.difference(list_1, list_2)`
* `llogic.intersection(list_1, list_2)`
* `llogic.is_contained(list_1, list_2)`
* `llogic.mixed_type(input_list)`
* `llogic.single_type(input_list)`
* `llogic.symmetric_difference(list_1, list_2)`
* `llogic.union(list_1, list_2)`

* `listools.concat_flatten(*input_lists)`
* `listools.flatten(input_list)`
* `listools.index_flatten(element, input_list)`
* `listools.len_flatten(input_list)`
* `listools.partial_flatten(input_list[, depth])`
* `listools.reverse_sorted_flatten(input_list)`
* `listools.sorted_flatten(input_list)`
* `listools.sum_flatten(input_list)`
* `listools.zip_cycle_flatten(*input_lists)`
* `listools.zip_cycle(*input_iters)`