Standardize on 127.0.0.1 for oauth in dev

This addresses #1434. In development we use dev versions of our oauth
apps at Twitter, GitHub, and Bitbucket. Twitter doesn't allow us to use
localhost for the app location, but they do allow 127.0.0.1, which the
others allow as well. This standardizes on that so we have a consistent
experience in dev when working with multiple connected accounts.