Add a way to specify npm publish access (private or public)

[trusktr]

See here:

cli/scripts/postversion.sh

Lines 4 to 5 in 5302760

	# TODO a way for projects to specify --access
	npm publish --access public

I've been publishing only "public" packages, even if they are published to a private registry. I haven't actually published "private" packages before. But someone may eventually need to do this.