Looking at the error caused by loading two items with the same id asynch...

I know it does not really fit the tests but I wanted to demonstrate the error I was seeing in https://github.com/emberjs/data/issues/1362.  I have not had time to familiarize myself with all the new paradigms in ember-data (new job & new twins) so I would not be shocked to learn I might just be implementing something wrong.

I believe this will run that test: [http://localhost:9292/?package=ember-data&testNumber=188](http://localhost:9292/?package=ember-data&testNumber=188)