Quiet mode - hide repos that are already up to date

[elyscape]

I have several hundred repos in my gitup bookmarks, and many of them don't have updates when I run gitup. It would be nice if there were a way to have gitup stifle output for repos that didn't have any updates.

[earwig]

Yes, this is a good idea: I did some work on it in response to #38 but got distracted and never finished. I will get around to it eventually, I promise!

[PilleOnline]

Any chance on this being done? I have a lot of repos checked out, and it's enough for me to see the the errors only (and maybe a statistic at the end (6 updated, 3 error, 39 without updates, ...))