timezone handling

[DerManoMann]

Is there any reason to set the timezone in getRunDate() if a properly configured $curentTime is set?
I need to validate cronlines against different timezones and it would be nice if timezone is only set if the provided $currentTime is null.

Nice code otherwise :)

[mtdowling]

Hm. I don't remember why I set the timezone there. Maybe it should only set the timezone if the DateTime object is created by the method (and not passed in).

[DerManoMann]

Exactly my thoughts. Is that something you could just do or do you want a PR for that?