Merge branch 'tb/diffstat-with-utf8-strwidth'

"git diff --stat" etc. were invented back when everything was ASCII and strlen() was a way to measure the display width of a string; adjust them to compute the display width assuming UTF-8 pathnames. * tb/diffstat-with-utf8-strwidth: diff: leave NEEDWORK notes in show_stats() function diff.c: use utf8_strwidth() to count display width