Using Ember.get for interpolations

For the following strcutured interpolation functionality:
   {{t "User {{contact.firstName}} {{contact.lastName}}" contact=xxx}}

While till this patch this has to be done as follows:
   {{t "User {{firstName}} {{lastName}}" firstName=xxx.firstName lastName=xxx.lastName}}
Merge pull request #177 from opichals/use-em-get-for-interpolations

Using Ember.get for interpolations