[ADD] - Added PHP version warning. It's time to move on from php 5.x
[ADD] - Added frontend page where subscribers can unsubscribe from all of the lists of a certain customer
[ADD] - Added the [UNSUBSCRIBE_FROM_CUSTOMER_URL] and [UNSUBSCRIBE_FROM_CUSTOMER_LINK] tags for the above page
[CHG] - 2FA uses local uri instead of the initial google uri
[ADD] - Added new option for RSS/JSON: send-only-unique-items
[MSC] - Small fixes overall