Omit minutes in the `frames` module if they're zero
IMO 49.64 is better than 00:49.64. Hours are already omitted if zero, so I think minutes should too.
For reference, the frames module uses the same time format as our submissions, publications, userfiles, and all the other places where time is displayed. For me, the overall reason why minutes are always displayed was basically because it seemed people would usually write (manually)
- 27:10 meaning 27 minutes and 10 seconds, and then
- 27.10 meaning 27 seconds and 10 centiseconds.
But visually you can see only a small difference. So then it was much easier immediately see 00:27.10 being mere seconds. That's for the submissions and publications of course. I just wanted to elaborate why things are how they are.
(I personally come to like the "27m 10s" type of writing lengths much more than any other way, even if it's more localized to English languages, but that's a different story.)