Remove unnecessary require
Remove unused variables
Remove unnecessary comment
because http://discuss.emberjs.com/t/documentation-needs-api-is-it-only-for-singleton-controllers/911/3
Merge pull request #2797 from tricknotes/remove-unnecessary-require

Remove unnecessary require
Merge pull request #2798 from tricknotes/remove-unused

Remove unused
Fix naming of _displayPropertyDidChange in comment
Merge pull request #2802 from ghedamat/rename-display-property-did-change

Fix naming of _displayPropertyDidChange in comment
Merge pull request #2800 from gilesbowkett/document-needs-only-for-singletons

document that 'needs' is for singleton controllers only
Fix typo in array mixin docs
Merge pull request #2806 from javierav/fix-docs

Fix typo in array mixin docs