This patch creates new "bisect.c" and "bisect.h" files and move
bisect related code into these files.
While at it, we also remove some include directives that are not
needed any more from the beginning of "builtin-rev-list.c".
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>