Fix iterate method.

As posted on https://github.com/icambron/twix.js/commit/7ae3af371529b6337a2c07a012aa2c7c7be60f28#commitcomment-8091275

> This is a breaking change in the way #iterate behaves with all day ranges. It is now also inconsistent with #count.
> 
> #iterateInner (and #countInner) already show the behavior #iterate has now been broken to show, so why was this change needed at all?

This reverts this breaking change. If the change was intentional, I'm curious about the reason.