The blame window shows "who wrote the piece originally" and "who
moved it there" in two columns. In order to identify the former
more correctly, it helps to use the new -w option.
[sp: Minor change to only enable -w if underlying git >= 1.5.3]
Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>