Don't bother with Ember.run.once, as we can detect an impending flush
by inspecting the size of the local queue of _deferredTriggers

This should mitigate some costly run-loop pressure.

Inspired to help with: https://github.com/ebryn/backburner.js/issues/51
another quick fix, which should reduce run-loop pressure.
WIP ES6 lol
move grunt tasks into folders
move some requires around
Do not call adapter.deleteRecord for a record that is already saved and deleted.
Remove DS.AttributeChange.
Merge branch 'master' of https://github.com/emberjs/data into es6

Conflicts:
	packages/activemodel-adapter/lib/system/active_model_adapter.js
	packages/activemodel-adapter/lib/system/active_model_serializer.js
	packages/ember-data/lib/system/model/model.js
	tests/ember_configuration.js
add watch option, fix some test oddities
Do not trigger didSetProperty if value is unchanged.

Also, fix determination of oldValue (previous a falsy value would not be
found in `this._attributes`).
Updates DS.Model.rollback documentation

I think `which` is not supposed to be there, the sentence turns weird.
Merge pull request #1684 from locks/patch-1

Updates DS.Model.rollback documentation
fix banner generation a bit
Merge branch 'master' of https://github.com/emberjs/data into es6

Conflicts:
	packages/activemodel-adapter/lib/system/active_model_adapter.js
	packages/ember-data/lib/adapters/rest_adapter.js
	packages/ember-data/lib/initializers.js
	packages/ember-data/tests/integration/application_test.js
fix build, import more test helper definitions from ember-dev
readd ContainerProxy to DS namespace
update README with grunt workflow
update ember
add grunt and bower install to .travis.yml
Remove unused helper.