bisect--helper: reimplement `bisect_visualize()` shell function in C
Reimplement the `bisect_visualize()` shell function
in C and also add `--bisect-visualize` subcommand to
`git bisect--helper` to call it from git-bisect.sh.
Mentored-by: Christian Couder <chriscool@tuxfamily.org> Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com> Signed-off-by: Miriam Rubio <mirucam@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>