Geo::Coder::Many::Scheduler::OrderedList - Ordered list scheduler
This is a scheduler representing a strict preferential order - it will always use the first geocoder in the list, unless it fails, in which case it'll fall back to the second in the list, and then the third, and so on.
Resets the list back to how it was initially set.
Returns the next item in the list.
Returns zero if there are items available, and -1 if there aren't.