Add ember-i18n [author]

cf https://github.com/jamesarosen/ember-i18n/issues/179

Ember-I18n is [published to npm](https://www.npmjs.com/package/ember-i18n), though the only versions that have a `dist/` folder are v3.0.0-beta1 and -beta2. I can't retroactively add `dist/` folders to older versions, though I *could* add patch releases for each of them.