Martin Geisler <mg@aragost.com> [Mon, 09 May 2011 16:41:45 +0200] rev 14280
progress: add speed format
This is not enabled by default, but the user can add it by setting
progress.format.
We might want to let the estimate format output a speed instead of an
ETA if there is not total. Currently estimate just returns the empty
string in that case.