Increase Dyn DNS timeout to 60, with a retry backoff.

We've had a rash of Dyn DNS API calls time out recently. In a support ticket with them, they suggested a longer retry period, with less frequent requests after 10 seconds.

This new code runs but has NOT been tested because at the moment their jobs are running fast enough to return status 200, not 307. If the direction of this change is acceptable, I'll do more to ensure it is tested thoroughly.