Add test for relative time with `format` argument
Add test for relative time with `format` argument

SSS2557/ember-intl,SSS2557/ember-intl,jasonmit/ember-intl,stefanpenner/ember-intl,al3x-edge/ember-intl,ember-intl/ember-intl,yahoo/ember-intl,mdehoog/ember-intl,null-null-null/ember-intl,jasonmit/ember-intl,al3x-edge/ember-intl,yahoo/ember-intl,ember-intl/ember-intl,elwayman02/ember-intl,ember-intl/ember-intl,elwayman02/ember-intl,stefanpenner/ember-intl,null-null-null/ember-intl,mdehoog/ember-intl