Add tests for calling jQuery.ajax from DS.RESTAdapter
Fix: unload record with relationships

- calling `clearRelationships` before changing record state,
  otherwise it fails, because properties try to update removed
  relationships

- Transaction commit failed when an unloaded record was in the
  `transaction.bucketForType.updated` array. Using recordIsMoving fixed
  this issue
Only setting content-type to JSON if there actually is content.
Merge branch 'master' of github.com:enyo/data
Added a test for the content-type.
fix test description
Warn if an application lacks a Store property

Attempts to use model class related methods that alias
to the store currently throw
`TypeError: Cannot read property 'find' of undefined`

This commit improves the message and offers a suggested
solution.
Fixed trailing commas which breaks IE7.
fixed issue #582
added adapter integration test for dirtyRecordsForAttributeChange
Update Readme unit test section
Wrap a run loop around simulated remote calls
add fixture serializer
use adapter interface in fixture adapter
Merge pull request #716 from tchak/fixture-adapter-cleanup

Fixture adapter cleanup
Implement extractHasMany and extractBelongsTo
Merge pull request #718 from tchak/fixture-adapter-cleanup

Implement extractHasMany and extractBelongsTo on FixtureAdapter
Introduce a custom `keyForHasMany()` for `DS.RESTSerializer`.

This method returns the singularized key appended with `_ids`. It uses the same plurals hash on the serializer to determine singular versions of keys.

Fixes #710
Failing test: 'When a record is loaded a second time, isLoaded should stay true'
Merge pull request #713 from bradfol/readme-tests

Update Readme Unit Test section