Support camelcase resolving of controllers in `needs` array

if a `needs` array contains a camel case name for a nested controller http://emberjs.com/api/classes/Ember.ControllerMixin.html#property_needs 

This program fails on ember-app-kit because the resolver cannot find controller:postComment since it is not handled, which means discrepancy from the ember js syntax for `needs`.
http://emberjs.jsbin.com/iKAyIjIf/10/edit