Commits from non GitHub users dont have author/committer objects

If there is a commit in a repo by a user that doesn't have a GitHub
login (or its not setup properly) we don't get the full author object
but we can at least get the user's email this way.
Add docs
Merge pull request #166 from clundie/feature/gist-html-url

Add HTMLURL property to OCTGist
Merge pull request #168 from jacksonh/nonGitHubUsers

Commits from non GitHub users dont have author/committer objects
Merge remote-tracking branch 'origin/master'