Unclear iteraction between iter skip values and start/end times

[andrewbaxter]

For jobs.iter but could apply elsewhere.

If start=10 and startts=100000 will it

• skip 10 results after time 100000 or will it
• return results that are at least 10 from the start and after time 100000
• return results that are at least 10 from the most recent and no older than time 100000 (re: ambiguity in Jobs.iter_last start and start_after parameters undocumented #136 )?

The same question about endts and start.