Fix rollback on invalid record after set
Fix error assertion's message

This fixes the error message to reflect the changes described in [Defining Relationships in Models](https://github.com/emberjs/data/blob/master/TRANSITION.md#defining-relationships-in-models).
Fix incorrect documentation for isError.

If the server returns a validation error, then isError is not set to true.
Drop spurious var set statements
Bring back deprecated initializers

Libraries such as ic-ajax are dependent on the old initializers in
ember-data (such as "store"). This brings them back temporarially, but
they will eventually be removed and are non-functional.
Extend from Controller for ApplicationController.
Merge pull request #1873 from abuiles/tests-typo

Extend from Controller for ApplicationController.
Merge pull request #1755 from alexspeller/fix-rollback-on-invalid-record-after-set

Fix rollback on invalid record after set
Add examples to the DS.Errors api docs.
add bower to getting ember data section
Merge pull request #1882 from knownasilya/patch-1

add bower to getting ember data section
Update changelog for initializer and container setup changes
Merge pull request #1867 from mixonic/cleanup-initializers

Cleanup initializers
Fix validation comments for

- Api docs included comments on failing client-side validation
- DS.model doesn't have client side validation
- Only code that sets errors and changes  is a result
  of an invalid response from server
[DOC beta] Clarify adapter settings with ActiveModel::Serializers
allow saving records from invalid state

tests by @alexspeller
Import InvalidError instead of looking at global DS
Merge pull request #1891 from Kerrick/remove-reliance-on-global-ds

Import InvalidError instead of looking at global DS
Add a better transform example
[DOC] Fix docs for method signature of extractSingle, extractArray