document github_token
rename "github_token" to "github-token"
Merge pull request #18 from rlidwka/github_token

rename "github_token" to "github-token"
Merge commit 'a938e888d7952b176f1e1c6a62e3cb59175efed3'
Merge https://github.com/visionmedia/npm

Conflicts:
	README.md
	lib/cache.js