Update the dvcs branch for ES6

Review Request #8056 — Created March 12, 2016 and submitted — Latest diff uploaded

Information

Review Board
dvcs

Reviewers

This patch updates the RB.DiffCommit model and
RB.DiffCommitIndexView view to use ES6. As well, the doc comments
have been updated to align with our style guide.

Manually tested that the diff commit index still worked.