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

* 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

"git tag" started listing a tag "foo" as "tags/foo" when a branch
named "foo" exists in the same repository; remove this unnecessary
disambiguation, which is a regression introduced in v2.7.0.

* jk/list-tag-2.7-regression:
  tag: do not show ambiguous tag names as "tags/foo"
  t6300: use test_atom for some un-modern tests

The ignore mechanism saw a few regressions around untracked file
listing and sparse checkout selection areas in 2.7.0; the change
that is responsible for the regression has been reverted.

* nd/exclusion-regression-fix:
  Revert "dir.c: don't exclude whole dir prematurely if neg pattern may match"

The documentation has been updated to hint the connection between
the '--signoff' option and DCO.

* dw/signoff-doc:
  Expand documentation describing --signoff

Since b7cc53e9 (tag.c: use 'ref-filter' APIs, 2015-07-11),
git-tag has started showing tags with ambiguous names (i.e.,
when both "heads/foo" and "tags/foo" exists) as "tags/foo"
instead of just "foo". This is both:

  - pointless; the output of "git tag" includes only
    refs/tags, so we know that "foo" means the one in
    "refs/tags".

and

  - ambiguous; in the original output, we know that the line
    "foo" means that "refs/tags/foo" exists. In the new
    output, it is unclear whether we mean "refs/tags/foo" or
    "refs/tags/tags/foo".

The reason this happens is that commit b7cc53e9 switched
git-tag to use ref-filter's "%(refname:short)" output
formatting, which was adapted from for-each-ref. This more
general code does not know that we care only about tags, and
uses shorten_unambiguous_ref to get the short-name. We need
to tell it that we care only about "refs/tags/", and it
should shorten with respect to that value.

In theory, the ref-filter code could figure this out by us
passing FILTER_REFS_TAGS. But there are two complications
there:

  1. The handling of refname:short is deep in formatting
     code that does not even have our ref_filter struct, let
     alone the arguments to the filter_ref struct.

  2. In git v2.7.0, we expose the formatting language to the
     user. If we follow this path, it will mean that
     "%(refname:short)" behaves differently for "tag" versus
     "for-each-ref" (including "for-each-ref refs/tags/"),
     which can lead to confusion.

Instead, let's add a new modifier to the formatting
language, "strip", to remove a specific set of prefix
components. This fixes "git tag", and lets users invoke the
same behavior from their own custom formats (for "tag" or
"for-each-ref") while leaving ":short" with its same
consistent meaning in all places.

We introduce a test in t7004 for "git tag", which fails
without this patch. We also add a similar test in t3203 for
"git branch", which does not actually fail. But since it is
likely that "branch" will eventually use the same formatting
code, the test helps defend against future regressions.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>