--help option and help command should print to stdout not stderr

--help and help are successfull commands so output should not go to error.

QE teams have requested this change, also users doing docker help | less
or docker run --help | less would expect this to work.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)

Conflicts:
	api/client/commands.go
	docker/docker.go
	docs/man/docker-attach.1.md
	docs/man/docker-build.1.md
	docs/man/docker-commit.1.md
	docs/man/docker-cp.1.md
	docs/man/docker-diff.1.md
	docs/man/docker-events.1.md
	docs/man/docker-export.1.md
	docs/man/docker-history.1.md
	docs/man/docker-images.1.md
	docs/man/docker-import.1.md
	docs/man/docker-inspect.1.md
	docs/man/docker-kill.1.md
	docs/man/docker-load.1.md
	docs/man/docker-login.1.md
	docs/man/docker-logs.1.md
	docs/man/docker-port.1.md
	docs/man/docker-ps.1.md
	docs/man/docker-pull.1.md
	docs/man/docker-push.1.md
	docs/man/docker-restart.1.md
	docs/man/docker-rm.1.md
	docs/man/docker-rmi.1.md
	docs/man/docker-run.1.md
	docs/man/docker-save.1.md
	docs/man/docker-search.1.md
	docs/man/docker-start.1.md
	docs/man/docker-stop.1.md
	docs/man/docker-tag.1.md
	docs/man/docker-top.1.md
	docs/man/docker-wait.1.md
	runconfig/parse.go