Increase the polling interval with each re-try

[Flix6x]

          We could increase the step/interval size with each re-try. 

I've seen that in practice, a slightly exponential function with poll_step as input is used.
If we double the amount of seconds each time (like the WP article example does), we could then start with a smaller value for request_step.

Originally posted by @nhoening in #2 (comment)