Add path, position, and body properties to pull request comments.
Correct implementation and comments for position / originalPosition
Add the commitSHA property to pull request comments.
Add original_commit_id, clarify docs, add more tests.
Merge pull request #109 from jacksonh/prProps

Add commitSHA, path, position, originalPosition, and body properties to pull request comments.
Add creationDate, updatedDate, and body to issue comments.
Add tests for OCTIssueComments
Add the body property to pull request comments.
Add a protocol for comments.