Merge remote branch 'ko/master' into HEAD

Merge remote branch 'ko/master' into HEAD

* ko/master: (366 commits)
  Update draft release notes to 1.6.6 before merging topics for -rc1
  Makefile: do not clean arm directory
  Add a notice that only certain functions can print color escape codes
  builtin-apply.c: pay attention to -p<n> when determining the name
  gitworkflows: Consistently back-quote git commands
  Explicitly truncate bswap operand to uint32_t
  t1200: fix a timing dependent error
  Documentation: update descriptions of revision options related to '--bisect'
  Enable support for IPv6 on MinGW
  Refactor winsock initialization into a separate function
  t/gitweb-lib: Split HTTP response with non-GNU sed
  pack-objects: split implications of --all-progress from progress activation
  instaweb: restart server if already running
  prune-packed: only show progress when stderr is a tty
  remote-curl.c: fix rpc_out()
  Protect scripted Porcelains from GREP_OPTIONS insanity
  mergetool--lib: simplify guess_merge_tool()
  strbuf_add_wrapped_text(): skip over colour codes
  t4014-format-patch: do not assume 'test' is available as non-builtin
  Fix over-simplified documentation for 'git log -z'
  ...