Iterator should internally not make use of toStream() anymore

[danieldietrich]

Instead we should implement stateful Iterators that achieve the same functionality. The reason is memory-efficiency.

• foldRight(Object, BiFunction)
• partition(Predicate)
• reduceRight(BiFunction)
• slideBy(Function)
• span(Predicate)
• unfoldLeft(Object, Function)
• unzip(Function)
• unzip3(Function)

[danieldietrich]

Closing the issue, Iterator now does not contain toStream() anymore. Thx @ruslansennov for fixing it!

[danieldietrich]

Will re-open it, also Stream.ofAll(...) should not be used anymore by Iterator internally.

[danieldietrich]

Note: Iterator does not extends Traversable anymore. It might be an option not to implement all methods.