Add the http.pinnedpubkey configuration option for public key
pinning. It allows any string supported by libcurl --
base64(sha256(pubkey)) or filename of the full public key.

If cURL does not support pinning (is too old) output a warning to the
user.

Signed-off-by: Christoph Egger <christoph@christoph-egger.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

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

* lv/add-doc-working-tree:
  git-add doc: do not say working directory when you mean working tree

Documentation for "git fetch --depth" has been updated for clarity.

* ss/clone-depth-single-doc:
  docs: clarify that --depth for git-fetch works with newly initialized repos
  docs: say "commits" in the --depth option wording for git-clone
  docs: clarify that passing --depth to git-clone implies --single-branch

* sg/t6050-failing-editor-test-fix:
  t6050-replace: make failing editor test more robust

* ew/for-each-ref-doc:
  for-each-ref: document `creatordate` and `creator` fields

Drop a few old "todo" items by deciding that the change one of them
suggests is not such a good idea, and doing the change the other
one suggested to do.

* ss/user-manual:
  user-manual: add addition gitweb information
  user-manual: add section documenting shallow clones
  glossary: define the term shallow clone
  user-manual: remove temporary branch entry from todo list

The underlying machinery used by "ls-files -o" and other commands
have been taught not to create empty submodule ref cache for a
directory that is not a submodule.  This removes a ton of wasted
CPU cycles.

* jk/ref-cache-non-repository-optim:
  resolve_gitlink_ref: ignore non-repository paths
  clean: make is_git_repository a public function

dirname() emulation has been added, as Msys2 lacks it.

* js/dirname-basename:
  mingw: avoid linking to the C library's isalpha()
  t0060: loosen overly strict expectations
  t0060: verify that basename() and dirname() work as expected
  compat/basename.c: provide a dirname() compatibility function
  compat/basename: make basename() conform to POSIX
  Refactor skipping DOS drive prefixes

* tb/complete-word-diff-regex:
  completion: complete "diff --word-diff-regex="