b29bd5ca3b
Our blame viewer has had a very fancy progress bar at the bottom of the window that shows the current status of the blame engine, which includes the number of lines completed as both a text and a graphical meter. I want to reuse this meter system in other places, such as during a branch switch where read-tree -v can give us a progress meter for any long-running operation. This change extracts the code and refactors it as a widget that we can take advantage of in locations other than in the blame viewer. Signed-off-by: Shawn O. Pearce <spearce@spearce.org>