[GSoC][PATCH v4 0/4] rebase: split rebase -p from rebase -i

This splits the `rebase --preserve-merges` functionnality from git-rebase--interactive.sh. All the dead code left by the duplication of git-rebase--interactive.sh is also removed. This will make it easier to rewrite this script in C.

This patch series is based of js/sequencer-and-root-commits.

Changes since v3:

 - Rewording the commits to be more descriptive, and to respect the 72
   characters limit.

Alban Gruin (4):
  rebase: introduce a dedicated backend for --preserve-merges
  rebase: strip unused code in git-rebase--preserve-merges.sh
  rebase: use the new git-rebase--preserve-merges.sh
  rebase: remove -p code from git-rebase--interactive.sh

 .gitignore                     |    1 +
 Makefile                       |    2 +
 git-rebase--interactive.sh     |  802 +------------------------------
 git-rebase--preserve-merges.sh | 1012 ++++++++++++++++++++++++++++++++++++++++
 git-rebase.sh                  |   32 +-
 5 files changed, 1048 insertions(+), 801 deletions(-)
 create mode 100644 git-rebase--preserve-merges.sh