[BUGFIX beta] Enable setProperties to work on Object.create(null) object.
Merge pull request #5647 from rwjblue/ember-keys-for-set-properties

[BUGFIX beta] Enable setProperties to work on Object.create(null) object.
Remove duplicate _MetamorphView
Minor changes to collection and view helpers

Based on feedback from
[here](https://github.com/emberjs/ember.js/commit/94510518341b14b67560623d774c92f2c4645fec).
Merge pull request #5649 from twokul/prop-fix

Minor changes to collection and view helpers
Merge pull request #5597 from mmun/two-metamorphs-walk-into-a-bar

Remove duplicate _MetamorphView