Changes 1.8.0:
UI, Workflows & Features
* A credential helper for Win32 to allow access to the keychain of
  the logged-in user has been added.
* An initial port to HP NonStop.
* A credential helper to allow access to the Gnome keyring has been
  added.
* When "git am" sanitizes the "Subject:" line, we strip the prefix from
  "Re: subject" and also from a less common "re: subject", but left
  the even less common "RE: subject" intact.  Now we strip that too.
* It was tempting to say "git branch --set-upstream origin/master",
  but that tells Git to arrange the local branch "origin/master" to
  integrate with the currently checked out branch, which is highly
  unlikely what the user meant.  The option is deprecated; use the
  new "--set-upstream-to" (with a short-and-sweet "-u") option
  instead.
* "git cherry-pick" learned the "--allow-empty-message" option to
  allow it to replay a commit without any log message.
* After "git cherry-pick -s" gave control back to the user asking
  help to resolve conflicts, concluding "git commit" used to need to
  be run with "-s" if the user wants to sign it off; now the command
  leaves the sign-off line in the log template.
* "git daemon" learned the "--access-hook" option to allow an
  external command to decline service based on the client address,
  repository path, etc.
* "git difftool --dir-diff" learned to use symbolic links to prepare
  a temporary copy of the working tree when available.
* "git grep" learned to use a non-standard pattern type by default if
  a configuration variable tells it to.
* Accumulated updates to "git gui" has been merged.
* "git log -g" learned the "--grep-reflog=<pattern>" option to limit
  its output to commits with a reflog message that matches the given
  pattern.
* "git merge-base" learned the "--is-ancestor A B" option to tell if A is
  an ancestor of B.  The result is indicated by its exit status code.
* "git mergetool" now allows users to override the actual command used
  with the mergetool.$name.cmd configuration variable even for built-in
  mergetool backends.
* "git rebase -i" learned the "--edit-todo" option to open an editor
  to edit the instruction sheet.

(adam)