no issue
- override `x-file-input` in `gh-file-input` to look for a custom property on the change event if we are in testing mode (this is necessary because Ember 2.5+ use native rather than jQuery events so `target.files` is readonly, see https://github.com/emberjs/ember.js/issues/13540)
- migrate unit tests for the uploader components to the integration tests
- add skipped acceptance tests for the subscribers CSV import now that it's possible to simulate file uploads
