Merge branch 'db/cover-letter'

Merge branch 'db/cover-letter'

* db/cover-letter:
  Improve collection of information for format-patch --cover-letter
  Add API access to shortlog
  t4014: Replace sed's non-standard 'Q' by standard 'q'
  Support a --cc=<email> option in format-patch
  Combine To: and Cc: headers
  Fix format.headers not ending with a newline
  Add tests for extra headers in format-patch
  Add a --cover-letter option to format-patch
  Export some email and pretty-printing functions
  Improve message-id generation flow control for format-patch
  Add more tests for format-patch

Conflicts:

	builtin-log.c
	builtin-shortlog.c
	pretty.c