Fix RRule.from iterator to return it with the time zone properly set.

Look at the the code below:

```scala
val dt = aDateTime.withZone(nonLocalTimeZone)
val it = RRule(DAILY) from dt
```

The original RRule.from method returned an iterator with the local time zone set. I think people would expect that it preserves the time zone from the DateTime instance provided.

I think that would fix the failing build in Travis introduced by the earlier pull request.