Throw and error if a user attempts to add a `data` property to a subclass of DS.Model
Merge pull request #2093 from bmac/data-is-reserved-prop

Throw and error if a user attempts to add a `data` property to a subclas...
Moved several normalize helper methods to the JSONSerializer
- Move `normalizeAttributes` to the `JSONSerializer` (mirrors `serializeAttributes`)
- Move `normalizeRelationships` to the `JSONSerializer`
- Move `normalizePayload` to the `JSONSerializer`
Merge pull request #2039 from bmac/jsonserializer-normaliz

Moved several non sideloaded related methods to the JSONSerializer
Added id and requestType back to extract* hooks

id and requestType parameters went missing in when removing aliasMethod. See commit dd964d2b7fe87ef7368336bd401c40834950f736 :
https://github.com/emberjs/data/commit/dd964d2b7fe87ef7368336bd401c40834950f736