Use Em.computed.sort and Em.computed.limit instead of nesting proxies

With new array computed helpers we can simplify code and get rid of
nested array proxies.

assets/scripts/app/controllers/repos.coffee

@@ -36,13 +36,14 @@ Travis.ReposController = Ember.ArrayController.extend
     Visibility.every Travis.INTERVALS.updateTimes, @updateTimes.bind(this)
 
   recentRepos: (->
-    Travis.LimitedArray.create
-      content: Em.ArrayProxy.extend(Em.SortableMixin).create(
-        sortProperties: ['sortOrder']
-        content: Travis.Repo.withLastBuild()
-        isLoadedBinding: 'content.isLoaded'
-      )
+    Ember.ArrayProxy.extend(
+      isLoadedBinding: 'repos.isLoaded'
+      repos: Travis.Repo.withLastBuild()
+      sorted: Ember.computed.sort('repos', 'sortedReposKeys')
+      content: Ember.computed.limit('sorted', 'limit')
+      sortedReposKeys: ['sortOrder:asc']
       limit: 30
+    ).create()
   ).property()
 
   updateTimes: ->