remove support for DS.FixtureAdapter

The FixtureAdapter has needed work for a long time, and without a
champion to maintain it, it is being moved out of core and into an
addon. You can see the addon at
https://github.com/emberjs/ember-data-fixture-adapter/tree/master.

We recommend you use an AJAX stubbing solution such as Pretender:
https://github.com/trek/pretender

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ### Master
 
+- Removed support for DS.FixtureAdapter. You can use it as an addon, or
+  build it using [Ember Giftwrap](https://github.com/ef4/ember-giftwrap).
+  https://github.com/emberjs/ember-data-fixture-adapter/tree/master
+
 ### Release 1.0.0-beta.18 (May 18, 2015)
 
 - [#3066](https://github.com/emberjs/data/pull/3066) Doc typo: primaryTypeClasss -> primaryTypeClass [@lolmaus](https://github.com/lolmaus)

README.md

@@ -117,12 +117,6 @@ adapter translates that into an XHR request to (for example)
 By default, Ember Data will use the `RESTAdapter`, which adheres to a
 set of RESTful JSON conventions.
 
-Ember Data also ships with the `FixtureAdapter`, useful for testing and
-prototyping before you have a server, and the `ActiveModelAdapter`,
-which is designed to work out-of-the-box with the
-[`ActiveModel::Serializers`](https://github.com/rails-api/active_model_serializers)
-gem for Rails.
-
 To learn more about adapters, including what conventions the
 `RESTAdapter` follows and how to build your own, see the Ember.js
 Guides: [Connecting to an HTTP

packages/ember-data/lib/adapters.js

@@ -2,10 +2,7 @@
   @module ember-data
 */
 
-import FixtureAdapter from "ember-data/adapters/fixture-adapter";
-import RESTAdapter from "ember-data/adapters/rest-adapter";
+import rest_adapter from "ember-data/adapters/rest-adapter";
+
+export var RESTAdapter = rest_adapter;
 
-export {
-  RESTAdapter,
-  FixtureAdapter
-};