Merge branch 'cc/sha1-bsearch' into HEAD

Merge branch 'cc/sha1-bsearch' into HEAD

* cc/sha1-bsearch: (95 commits)
  patch-ids: use the new generic "sha1_pos" function to lookup sha1
  sha1-lookup: add new "sha1_pos" function to efficiently lookup sha1
  Update draft release notes to 1.6.3
  GIT 1.6.2.2
  send-email: ensure quoted addresses are rfc2047 encoded
  send-email: correct two tests which were going interactive
  Documentation: git-svn: fix trunk/fetch svn-remote key typo
  Mailmap: Allow empty email addresses to be mapped
  Cleanup warning about known issues in cvsimport documentation
  Documentation: Remove an odd "instead"
  send-email: ask_default should apply to all emails, not just the first
  send-email: don't attempt to prompt if tty is closed
  fix portability problem with IS_RUN_COMMAND_ERR
  Documentation: use "spurious .sp" XSLT if DOCBOOK_SUPPRESS_SP is set
  mailmap: resurrect lower-casing of email addresses
  builtin-clone.c: no need to strdup for setenv
  builtin-clone.c: make junk_pid static
  git-svn: add a double quiet option to hide git commits
  Update draft release notes to 1.6.2.2
  Documentation: push.default applies to all remotes
  ...