Auto merge of #1164 - jsmestad:patch-3, r=locks
Auto merge of #1164 - jsmestad:patch-3, r=locks

Update formatCurrency helper to match Ember-CLI

When running `ember g helper format-currency` the generated file follows a different format than the guides show. This is using `ember-cli 2.2.0-beta.3`

boztek/guides,knownasilya/guides,greyhwndz/guides,greyhwndz/guides,jkarsrud/guides,tleskin/guides,MarkMT/guides,skaterdav85/guides,bmac/guides,boztek/guides,jkarsrud/guides,ubuntuvim/guides,tleskin/guides,tleskin/guides,davidpett/guides,nicobot/guides,ubuntuvim/guides,nicobot/guides,HeroicEric/guides,vikram7/guides,boztek/guides,HeroicEric/guides,HeroicEric/guides,MarkMT/guides,greyhwndz/guides,skaterdav85/guides,bmac/guides,jkarsrud/guides,davidpett/guides,vikram7/guides,knownasilya/guides,jkarsrud/guides,bmac/guides,MarkMT/guides,MarkMT/guides,ubuntuvim/guides,ubuntuvim/guides,bmac/guides,skaterdav85/guides,davidpett/guides,nicobot/guides,knownasilya/guides,knownasilya/guides,skaterdav85/guides,vikram7/guides,davidpett/guides