Changes extractSingle's return to call this._super

This makes the example in-line with the current documentation of DS.RESTSerializer.
I also was having trouble making extractSingle work in my application and making this change fixed it.
Reimplemented `rootForType`
Merge pull request #1212 from bradleypriest/rootForType

Reimplemented `rootForType`
added docs that show how to wire up a custom serializer
amend asynchronous belongsTo fix
Update ext.js documentation to use b1-style relationship definitions

e.g. hasMany(App.User) -> hasMany('user')
Add `store.update` to update just some attrs

This also moves the logic for transforms into `normalize` rather than
`push`, which fixes #1214.

It means that you should not rely on `push` to apply transforms, and
must do all normalization before pushing. A nice solution for streamed
data is coming.
Merge pull request #1210 from locks/patch-1

Changes extractSingle's return to call this._super
Merge pull request #1215 from daliwali/master

amend asynchronous belongsTo fix
Reorder the signature to `normalize`

This is a breaking change but necessary because `normalize` in
JSONSerializer doesn't have a sideloading property and we need
`normalize` in JSONSerializer to do transformations.
Updated URLs in the Readme
Merge pull request #1219 from Globegitter/patch-1

Updated URLs in the Readme
Merge pull request #1216 from nragaz/patch-3

Update ext.js documentation to use b1-style relationship definitions
Update CHANGELOG
Bump version
Remove unused store vars (thx @bradleypriest)

Fixes #1209
Add normalizePayload
Update normalize method signature in TRANSITION.md
Fixes version number in Changelog

And my name ;)
Fix changelog version number