Ember.Handlebars.get -> Ember.get

Now that we're using `Ember.Handlebars.registerBoundHelper` to construct
the `{{t}}` helper, we don't need to use `Ember.Handlebars.get`. It's
deprecated and does unnecessary work.
Ember-I18n 3.x supports Ember 1.x

 * relax Bower dependency on Ember to `^1.0`
 * resume testing against Ember canary
 * current Ember canary (what will be 1.9) relies on
   Handlebars 2.x
Merge pull request #166 from jamesarosen/james/resume-canary

Ember-I18n 3.x supports Ember 1.x