Merge branch 'master' into next

* master:
  send-email: do not pass bogus address to local sendmail binary
  Add a basic test case for git send-email, and fix some real bugs discovered.
  Fix a bug in email extraction used in git-send-email.
  Add support for --bcc to git-send-email.
  git-send-email: Add References: headers to emails, in addition to In-Reply-To:
  git-clean fails on files beginning with a dash
  git-svn: remove assertion that broke with older versions of svn
  git-svn: t0001: workaround a heredoc bug in old versions of dash
  Documentation: fix a tutorial-2 typo
  Documentation: retitle the git-core tutorial
  documentation: add brief mention of cat-file to tutorial part I
  documentation: mention gitk font adjustment in tutorial
  Fix some documentation typoes