Merge branch 'mn/send-email-works-with-credential' into next

Merge branch 'mn/send-email-works-with-credential' into next

Hooks the credential system to git-send-email.

* mn/send-email-works-with-credential:
  git-send-email: use git credential to obtain password
  Git.pm: add interface for git credential command
  Git.pm: allow pipes to be closed prior to calling command_close_bidi_pipe
  Git.pm: refactor command_close_bidi_pipe to use _cmd_close
  Git.pm: fix example in command_close_bidi_pipe documentation
  Git.pm: allow command_close_bidi_pipe to be called as method

Conflicts:
	perl/Git.pm