Merge pull request #85 from github/2fa-filter

Document filter for auditing 2FA
Clearly document scope normalization
Merge branch 'master' of https://github.com/github/internal-developer.github.com
Tweak copy
Merge pull request #86 from github/clarify-normalized-scopes

Clearly document scope normalization
Merge branch 'master' of https://github.com/github/developer.github.com