After upgrading ember to 1.8.1 tests pass, but I found a few cases where
things break (for example when navigating between certain routes). I'm
reverting for now.
This reverts commit fa5e9179af, reversing
changes made to 978c887123.
arrayComputed was added recently in order to make array computations
easier. Using arrayComputed we can improve LimitedArray which now uses
an isolated multipurpose Ember.computed.limit.
