emberjs/ember.js — pull request #789 by wagenet (2012-05-04 06:08:05+00:00)
Title: Re-enable enumerable properties: [], firstObject and lastObject

This were previously disabled due to over-zealous firing of firstObject and
lastObject. However, [] was still useful for non-array enumerables.
Additionally, firstObject and lastObject were made smarter so as to only fire
notifications when necessary.