title: Angular orderBy filter not sorting natural
body: <p>I have the following code:</p>
  
  <pre><code>&lt;html ng-app="myApp"&gt;
      &lt;head&gt;
          &lt;title&gt;Angular Demo&lt;/title&gt;
          &lt;script src="angular/angular.min.js"&gt;&lt;/script&gt;
          &lt;script src="js/controllers.js"&gt;&lt;/script&gt;
          &lt;script src="//code.jquery.com/jquery-1.10.2.js"&gt;&lt;/script&gt;
          &lt;script src="//code.jquery.com/ui/1.11.1/jquery-ui.js"&gt;&lt;/script&gt;
      &lt;/head&gt;
      &lt;body&gt;
          &lt;div ng-controller="myController"&gt;
              &lt;div ng-init="oras='Valcea'"&gt;&lt;/div&gt;
              &lt;input type="text" ng-model="search"&gt;&lt;br/&gt;&lt;br/&gt;
              &lt;select name="" id="" ng-model="eleviorder"&gt;
                  &lt;option value="name"&gt;Nume&lt;/option&gt;
                  &lt;option value="prenume"&gt;Prenume&lt;/option&gt;
                  &lt;option value="age"&gt;Varsta&lt;/option&gt;
                  &lt;option value="highscool"&gt;Liceu&lt;/option&gt;
                  &lt;option value="luckynumber"&gt;Numar norocos&lt;/option&gt;
              &lt;/select&gt;
              Ordonare Nume:&lt;label&gt;
                  &lt;input type="radio" name="direction" ng-model="direction" checked/&gt;ascending&lt;/label&gt;
              &lt;label&gt; 
                  &lt;input type="radio" name="direction" ng-model="direction" value="reverse"/&gt;descending
              &lt;/label&gt;
              &lt;ul&gt;
                  &lt;li ng-repeat="item in elevi | filter :search | orderBy :eleviorder :direction :myfunction"&gt;
                      &lt;div&gt;{{item.name}} {{item.prenume}}, Varsta:{{item.age}}, Liceu: {{item.highscool}}, Numar norocos: {{item.luckynumber}} Oras:{{oras}}&lt;/div&gt;
                  &lt;/li&gt;
              &lt;/ul&gt;
          &lt;/div&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>with this controller </p>
  
  <pre><code>var myApp = angular.module('myApp', []);
  
  myApp.controller('myController',['$scope','$http',function ($scope,$http){
      $http.get('js/data.json').success(function(data){
          $scope.elevi = data;
          $scope.eleviorder = 'name';
      });
  }]);
  </code></pre>
  
  <p>who get this data from data.json</p>
  
  <pre><code>[
      {"name":"Udrea",
      "prenume":"Alexandru",
      "age":"27",
      "highscool":"Henri Coanda",
      "luckynumber":"7"
      },
      {"name":"Rizea",
      "prenume":"Paul",
      "age":"23",
      "highscool":"Mircea Cel Batran",
      "luckynumber":"11"
      },
      {"name":"Popescu",
      "prenume":"Ion",
      "age":"19",
      "highscool":"Pedagogic",
      "luckynumber":"17"
      },
      {"name":"Popescu",
      "prenume":"Maria",
      "age":"18",
      "highscool":"Sanitar",
      "luckynumber":"8"
      },
      {"name":"Muscalu",
      "prenume":"Leonard",
      "age":"22",
      "highscool":"Forestier",
      "luckynumber":"47"
      },
      {"name":"Ionescu",
      "prenume":"Ema",
      "age":"29",
      "highscool":"Alexandru Lahovari",
      "luckynumber":"26"
      }
  ]
  </code></pre>
  
  <p>My problem is that i can't orderby the luckynumber in natural order it orders the luckynumber like this 11,17,26,47,7,8 instead of 7,8,11,17,26,47</p>