Change usages of Ember.create and Ember.keys to Object.create and Object.keys

[akshayrawat]

This leads to a lot of deprecation noise when working with Ember 1.13.2.

Happy to submit a PR if this is legit.

[stefanpenner]

We do want to switch, but this library needs to continue to work for 1.13.2 users who use ie8.

I guess Let's inline the two polyfills here

[stefanpenner]

#100