Return to user's last seen page on PaginatedState after timeout

[gsvr]

It would be ideal if this would also work if a special timeout state is interjected like in go-refugeerights state_timed_out.

[hodgestar]

I think this could be approached in one of two ways. Either we could add an option for setting and retrieving page_start (i.e. the current starting point for the list) or you could arrange for the go-refugeerights time out state to record the previous state's metadata in addition to its name and creator_opts. The latter solution covers all state types and so is probably better for go-refugeerights. Having the option of setting page_start might still be nice though.

[gsvr]

Yeah, I thought it might be two different implementations for with and without a timed_out state, but thought I'd leave that comment in case it could be architected to work for both. I think it would still be useful in the cases where we don't have a timed_out state.