Allow belongs to associations to be saved when the associated object is null.
Remove accidentally added capitalize and camelize
Add failing test for hasMany relationships

If adapter does not return any data for a hasMany relationship,
the unsaved hasMany records disappear from the relationship.
Fixes #1466
Always keep the hasMany around when payload arrives

We should always keep the current hasMany value if the payload
has no relationships with that key
Added documentation for ajaxError with DS.Errors.
Stop using deprecated methods

Replace to use some methods that Ember.js recommends.
* `findProperty` -> `findBy`
* `mapProperty` -> `mapBy`
* `filterProperty` -> `filterBy`
* `everyProperty` -> `isEvery`
Merge pull request #2034 from tricknotes/stop-using-deprecated-methods

Stop using deprecated methods
fix docs for Store#getById
Merge pull request #2037 from knownasilya/getById-docs

[DOC] Fix docs for Store#getById
Merge pull request #2030 from wbyoung/doc-ajax-error

Added documentation for ajaxError with DS.Errors.
[FIX] typeof null actually === 'object'

Fixed an issue where calling `isValue` with null would throw a
`TypeError` (Cannot read property then of null)
Add a starter JSBin with associations example.
Merge pull request #2042 from mehulkar/patch-1

Add a starter JSBin with associations example.
Docs use model on controller instead of route

Changed the documentation so that the model property referenced is on
the controller of the route rather than the route itself. Since the
route already has a method called model, referencing the model property
as an Ember-Data model can be confusing.
cleanup: align es6 (and other coding patterns) with ember's own
Merge pull request #2047 from stefanpenner/master

cleanup: align es6 (and other coding patterns) with ember's own
improve debug ergonomics (as I debug)

* re-using argument variables makes it quite hard to see the original value, also it has some negative performance side-effects.
* using the comma operator for long variable declarations, especially if they include method invocations makes it impossible to easily set breakpoints.
Merge pull request #2050 from stefanpenner/master

improve debug ergonomics (as I debug)
more breakpoint friendly refactoring