Merge branch 'js/fmt-patch'

Merge branch 'js/fmt-patch'

This makes "git format-patch" a built-in.

* js/fmt-patch:
  git-rebase: use canonical A..B syntax to format-patch
  git-format-patch: now built-in.
  fmt-patch: Support --attach
  fmt-patch: understand old <his> notation
  Teach fmt-patch about --keep-subject
  Teach fmt-patch about --numbered
  fmt-patch: implement -o <dir>
  fmt-patch: output file names to stdout
  Teach fmt-patch to write individual files.
  Use RFC2822 dates from "git fmt-patch".
  git-fmt-patch: thinkofix to show [PATCH] properly.
  rename internal format-patch wip
  Minor tweak on subject line in --pretty=email
  Tentative built-in format-patch.