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
Failing test: 'When a record is loaded a second time, isLoaded should stay true'
Warn, don't fail, when there are no fixtures
Fail rather than returning all fixtures when queryFixtures is not implemented
Add docs directory with package.json and yuidoc.json

`EMBER_PATH=../ember-data rake preview` in ember-website does not quite
work yet. I don't have time at the moment to get it working completely,
but let's have the docs directory as a starting point.
Add live query test for RecordArray
Merge pull request #700 from airportyh/fix_trailing_commas_ie7

Fixed trailing commas which breaks IE7.
Merge pull request #707 from CrowdStrike/missing-fixtures

Warn, don't fail, when there are no fixtures
Merge pull request #706 from CrowdStrike/query-fixtures

Fail rather than returning all fixtures when queryFixtures is not implemented
Merge pull request #689 from trek/improve-error-message-for-missing-store

Warn if an application lacks a Store property
Potential fix for #731