This reverts commit d96a275b91bae1800cd43be0651e886e7e042a17.

It used to be possible to apply a patch series with "git am mbox"
and then only after seeing a failure, switch to three-way mode via
"git am -3" (no other options or arguments).  The commit being
reverted broke this workflow.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Update to the "linked checkout" in 2.5.0-rc1.

Instead of "checkout --to" that does not do what "checkout"
normally does, move the functionality to "git worktree add".

* es/worktree-add: (24 commits)
  Revert "checkout: retire --ignore-other-worktrees in favor of --force"
  checkout: retire --ignore-other-worktrees in favor of --force
  worktree: add: auto-vivify new branch when <branch> is omitted
  worktree: add: make -b/-B default to HEAD when <branch> is omitted
  worktree: extract basename computation to new function
  checkout: require worktree unconditionally
  checkout: retire --to option
  tests: worktree: retrofit "checkout --to" tests for "worktree add"
  worktree: add -b/-B options
  worktree: add --detach option
  worktree: add --force option
  worktree: introduce "add" command
  checkout: drop 'checkout_opts' dependency from prepare_linked_checkout
  checkout: make --to unconditionally verbose
  checkout: prepare_linked_checkout: drop now-unused 'new' argument
  checkout: relocate --to's "no branch specified" check
  checkout: fix bug with --to and relative HEAD
  Documentation/git-worktree: add EXAMPLES section
  Documentation/git-worktree: add high-level 'lock' overview
  Documentation/git-worktree: split technical info from general description
  ...

"git checkout [<tree-ish>] <paths>" spent unnecessary cycles
checking if the current branch was checked out elsewhere, when we
know we are not switching the branches ourselves.

* nd/multiple-work-trees:
  worktree: new place for "git prune --worktrees"
  checkout: don't check worktrees when not necessary

Abandoning an already applied change in "git rebase -i" with
"--continue" left CHERRY_PICK_HEAD and confused later steps.

* js/rebase-i-clean-up-upon-continue-to-skip:
  rebase -i: do not leave a CHERRY_PICK_HEAD file behind
  t3404: demonstrate CHERRY_PICK_HEAD bug

A minor bugfix when pack bitmap is used with "rev-list --count".

* jk/rev-list-no-bitmap-while-pruning:
  rev-list: disable --use-bitmap-index when pruning commits

An ancient test framework enhancement to allow color was not
entirely correct; this makes it work even when tput needs to read
from the ~/.terminfo under the user's real HOME directory.

* rh/test-color-avoid-terminfo-in-original-home:
  test-lib.sh: fix color support when tput needs ~/.terminfo
  Revert "test-lib.sh: do tests for color support after changing HOME"

Code clean-up.

* sb/p5310-and-chain:
  p5310: Fix broken && chain in performance test

Test updates to a topic already in 2.5-rc.

* nd/dwim-wildcards-as-pathspecs:
  Add tests for wildcard "path vs ref" disambiguation

The for_each_packed_object() API function did not iterate over
objects in a packfile that hasn't been used yet.

* jk/maint-for-each-packed-object:
  for_each_packed_object: automatically open pack index

As a convenience, when <branch> is omitted from "git worktree <path>
<branch>" and neither -b nor -B is used, automatically create a new
branch named after <path>, as if "-b $(basename <path>)" was specified.
Thus, "git worktree add ../hotfix" creates a new branch named "hotfix"
and associates it with new worktree "../hotfix".

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>