Do not call adapter.deleteRecord for a record that is already saved and deleted.
Remove DS.AttributeChange.
Copy metadata when it is assigned to recordArrays

Currently metadata is saved on Model classes, such that there is
only ever 1 instance of the meta object in existence. Often however
metadata is a property of a particular array of records and not the
record type. A good example is pagination. It should be possible to
do `store.findQuery()` twice and get two arrays where each has it's
own meta information. However, because metadata is stored on the
Model class, any subsequent request will modify the original
pagination metadata. This commit enables each recordArray to have
it's own unchanging Meta object.
DS.EmbeddedRecordsMixin methods for serializing relationships call super if needed

[Fixes #1971]
[Docs] Update documentation for the EmbeddedRecordsMixin
Merge pull request #1967 from emberjs/metadataCopy

Copy metadata when it is assigned to recordArrays
Merge pull request #1671 from bmac/delete-saved-record

RESTAdapter suppress DELETE request when deleted record has already been saved
Merge pull request #1972 from pixelhandler/embedded-mixin-calls-super

DS.EmbeddedRecordsMixin methods for serializing relationships call super
Cleanup embedded docs
fix merge conflicts
v1.0.0-beta.8 Changelog
remove CHANGELOG cruft
changelog cleanup
Merge pull request #1969 from pixelhandler/ember-records-mixin-docs

[Docs] Update documentation for the EmbeddedRecordsMixin
Add missed changelog entries
ie8 fixes
Merge pull request #1983 from fivetanley/ie8-fixes

ie8 fixes
post-release version bump
Fixes #1973

Failure in Firefox when record id equals 'watch' .
Gecko adds watch function to Object.prototype (as described here:
https://developer.mozilla.org/ru/docs/Web/JavaScript/Reference/Global_Ob
jects/Object/watch)
add checking if Object.prototype.watch is exist

Object.prototype.watch function is used in model unit test to check a
collision of a record's id with object function's name.
So we create this function if needed and remove after test if it was
not defined before.