yahns 1.17.0 - Earth Day release

This releases includes a few kqueue-related bugfixes from
Lin Jen-Shin <godfat@godfat.org>.  There's also some
shutdown_timeout-related bugfixes and some cleanups to
reduce dependencies on kgio.

extras/exec_cgi and extras/autoindex both got some minor
updates; the latter of which defaults to a dark scheme to save
power on OLED and CRT displays (it is Earth Day, after all :>)

Eric Wong (25):
      doc: fix git URLs in README and HACKING
      http_client: do not warn on do_pread overreach
      remove IO#close_on_exec= calls
      yahns/worker: shrink pipe under Linux
      test/test_extras_exec_cgi.rb: improve test reliability
      extras/exec_cgi: remove kgio dependency
      extras/exec_cgi: update copyright year and use SPDX
      extras/exec_cgi: @body_tip is always set
      extras/exec_cgi: support Process.spawn options (e.g. RLIMIT_*)
      server_mp: favor "Kernel#select" instead of "IO.select"
      server_mp: remove redundant srand call
      extras/exec_cgi: remove unecessary .freeze calls
      server: respect shutdown_timeout
      server: extra shutdown timeout debugging
      wbuf: use IO#write directly in Ruby 2.5+ for writev
      worker: rely on F_SETPIPE_SZ to set mininum value
      remove calls to kgio_wait_* able
      do not shutdown until listeners are all stopped
      README: remove SMTP-based subscription info
      sigevent_*: fixup non-eventfd path
      README: note HTTPS support for HTTP/1.1
      extras/autoindex: use dark colors by default
      doc: update homepage to point to cgit install
      doc: update wording to avoid "mailing list"
      doc: remove inaccurate comment about "GNU-ism"

Lin Jen-Shin (2):
      Add QueueQuitter#closed? to queue_quitter_pipe.rb
      @srv.shutdown could raise Errno::ENOTCONN