helpers are not accessible to normal add-on consumers

- [ ] ember-data should no longer auto-include these helpers
- basically its a bug in this repo that they are included auto-matically
- i'll release 2.x with that fixed
- @bmac we should coordinate on another ember-inflector / ember-data release
- [ ] we should offer the helpers as an idiomatic ember-addon normally does. (although as they are non-dasherized, so forcibly included an initializer)