Use prototype comparison to check to see if adapters are the same typ…

…e instead of direct comparison. This fixes issue where each model has their own declared model adapter like ember-cli now requires. References issue: #68

localstorage_adapter.js

@@ -405,7 +405,7 @@
          * In this case, cart belongsTo customer and its id is present in the
          * main payload. We find each of these records and add them to _embedded.
          */
-        if (relationEmbeddedId && foreignAdapter === adapter)
+        if (relationEmbeddedId && DS.LSAdapter.prototype.isPrototypeOf(adapter))
         {
           recordPromise = recordPromise.then(function(recordPayload) {
             var promise;