Update to use module imports

[GCheung55]

https://github.com/emberjs/rfcs/blob/master/text/0176-javascript-module-api.md was merged and majority of modules have been made available on the @ember namespace.

ember-new-relic can use an update.

There are two problems that haven't been addressed, which is how to treat Ember.Logger and Ember.onerror. But these two problems shouldn't be a blocker to begin updating. :)

[sir-dunxalot]

Fixed by #28.