add documentation for setting an oauth token and the common rate limiting fault
bump librarian puppet to 0.9.9 from 0.9.8
Change GITHUB_API_KEY to GITHUB_API_TOKEN, because librarian-puppet expects it

See https://github.com/rodjek/librarian-puppet/blob/master/lib/librarian/puppet/source/githubtarball.rb#L117
Merge pull request #13 from lonnen/document-rate-limiting-error

add documentation for setting an oauth token