Migrated to Ember NuGet package, .NET v4.0.

Updated the main library to use the Ember.js package on NuGet. This
should make upgrading to newer Ember.js versions a bit easier in the
future.

Also changed from .NET 4.5 to .NET 4.0 to broaden the base of potential
users.
Merge pull request #5 from zgramana/master

Migrated to the Ember.js NuGet package, .NET v4.0.