Port RB.Diff to Backbone.js.
Review Request #3935 — Created March 5, 2013 and submitted
Port RB.Diff to Backbone.js. The resulting RB.Diff is pretty tiny, since it's just a thin wrapper over BaseResource's functionality now, and since the diff fragment support has moved into DiffReviewable. All it's used for now is for uploading new diffs. It provides an rspNamespace and a function for returning human-readable error strings, given an error payload.
Uploaded some diffs.