git-pickaxe -C: blame cut-and-pasted lines.

git-pickaxe -C: blame cut-and-pasted lines.

This completes the initial round of git-pickaxe.  In addition to
the detection of line movements we already have, this finds new
lines that were created by moving or cutting-and-pasting lines
from different files in the parent.

With this,

	git pickaxe -f -n -C v1.4.0 -- revision.c

finds that a major part of that file actually came from
rev-list.c when Linus split the latter at commit ae563642 and
blames them to earlier commits that touch rev-list.c.

Signed-off-by: Junio C Hamano <junkio@cox.net>