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.
Move createSerializedForm to DS.Serializer.  Serializer calls the routine currently, but it's only defined in the JSON and Fixture implementations.
Added 'isLoading' flag to DS.State
Switch serialized/deserialized argument names
Updated against master
Merge pull request #873 from JasonKriss/patch-1

Switch serialized/deserialized argument names
Merge pull request #815 from everwakeful/master

Extend existing "meta" solution for JSON REST responses
Fix belongsTo relationships to models with id 0
Merge pull request #876 from tricknotes/fix-belongs-to-relationships

Fix belongsTo relationships to models with id 0
Remove unused local variable
Merge pull request #877 from tricknotes/remove-unused

Remove unused local variable
Merge pull request #812 from zachriggle/master

Move createSerializedForm to DS.Serializer
Allow options.defaultValue of DS.attr to be a function

This change allows the defaultValue defined for a DS.attr to be a
function, so it is possible to do something like this:

```
User = DS.Model.extend({
  createdAt: DS.attr("date", {
    defaultValue: function() {
      return (new Date());
    }
  })
});
```

This closes #878
Remove duplicate #createSerializedForm method from DS.Serializer
Merge pull request #880 from pangratz/remove_duplicate_createSerializedForm

Remove duplicate #createSerializedForm method from DS.Serializer
Add missing property `namespace` to `DS.RESTAdapter`

It is kindness that public API is clearly specified.
Typo in Bulk DELETE test

This test labeled as issuing a `PUT` instead of a `DELETE`

The actual test code does make a `DELETE` request
Merge pull request #882 from southpolesteve/patch-1

Typo in Bulk DELETE test