bump ember-source to 1.0.0-rc.6
Modify code indent
Use `Ember.EnumerableUtils.forEach`
Use `Ember.EnumerableUtils.indexOf`
Use `Ember.EnumerableUtils.map`
fix testing description
Fix to ignore internal property for older IE

The for ~ in loop iterates internal property that defined by
`Ember.create`.
`Ember.keys` should be used to prevent this behavior for iterator.
Merge pull request #1054 from tricknotes/bump-ember-source

bump ember-source to 1.0.0-rc.6
Merge pull request #1055 from tricknotes/ie8

Support IE8