Records that could not be found can be retried

Fixes #1235
Fixed typo in doc comments: @property instead of @param
Merge pull request #1236 from davidsevcik/master

Fixed typo in doc comments: @property instead of @param
Fix invalid inline docs
Don't use likely-to-be-used IDs in fixtures

Fixes #1237
Add assertions that array fetches return arrays

Fixes #820
Merge pull request #1233 from bradleypriest/modelFromRoot

Add modelTypeFromRoot hook
Basic DS.ActiveModelSerializer implementation
custom JSON root
Get extraction working
rename rootForType hook to match
- Duplicate RESTSerializer serialize methods
- Basic polymorphic serialisation support