* Remove unnecessary type parameters
* Update transduce() and reduce() to accept CompletingTransformers
* Fix incorrect definition of transduce()
* Fix incorrect definition of reduce()
* Fix incorrect definition of completing()
* Fix incorrect definition of wrap()
* Fix incorrect definition of cat()
* Fix overly strict definition of mapcat()
* Make into() definition precise with overloads
* Use es6 Iterables.
* More precise typings for object iteration in reduce(), transduce(),
and into()