Update docs to recommend install rather than update

Close #5903
npmconf@2.1.0

Set and get always-auth on per-registry credentials.
npm-registry-client@3.2.2

Consume the new per-registry always-auth settings.
request@2.44.0
support saving --always-auth on adduser
use writeFileAtomic instead of fs.writeFile fixes #6163
reintroduce omitted chown (thx iarna!)
Allow init without prompt
init-package-json@1.1.0

part of #5925
update changelog for npm@2.0.1
2.0.1