title: Restangular.copy(): route on .one() object ends up undefined
body: <p>I'm having problems with Restangular's <strong>.one()</strong> and <strong>.put()</strong> functions. When I <strong>Restangular.copy()</strong> the element I need to work with, I lose the <strong>route</strong> value.</p>
  
  <p>If I manually add the <strong>route</strong> value I get it to work (example down below).</p>
  
  <p>My plan was to use resolves in <strong>$stateProvider</strong>, but this is still in testing-phase, that's why I'm looking for advice/need help.</p>
  
  <p>Am I doing something completely wrong?</p>
  
  <hr>
  
  <h2>API side:</h2>
  
  <pre><code>GET: /api/news/1
  </code></pre>
  
  <h3>Response:</h3>
  
  <pre><code>{
    "success":true,
    "status":200,
    "data": [
      {"id": 1, "title":"the title", "author":"the author", "date": 123456789, "contents": "the contents"}
    ]
  }
  </code></pre>
  
  <hr>
  
  <h2>Front-end side:</h2>
  
  <pre><code>'use strict';
  
  angular.module('app', ['ui.router', 'restangular'])
  .config(['RestangularProvider', '$stateProvider', function (RestangularProvider, $stateProvider) {
    RestangularProvider.setBaseUrl('/api');
  
    RestangularProvider.addResponseInterceptor(function (data, operation) {
      var extractedData;
  
      if (operation === 'getList') {
        extractedData         = data.data;
        extractedData.success = data.success;
        extractedData.status  = data.status;
      } else {
        extractedData = data;
      }
  
      return extractedData;
    });
  
    $stateProvider.state('news', {
      url: '/news/:id',
      views: {
        'articles': {
          controller: 'NewsCtrl',
          templateUrl: 'news-view.html'
        }
      }
    });
  }])
  .controller('NewsCtrl', ['$stateParams', 'Restangular', function ($stateParams, Restangular) {
  
    $stateParams.id = 1; // For the sake of this example
  
    Restangular.one('news', $stateParams.id).get().then(function (data) {
      console.log(data); // route set to news
  
      var post   = data.data[0]; // access the response object
      post.title = 'a news title';
      post.put(); // TypeError: undefined is not a function
  
      var anotherPost   = Restangular.copy(data.data[0]); // using Restangular.copy instead
      anotherPost.title = 'another news title';
      // anotherPost.route = 'news'; // if I add this to anotherPost, put() will work
      anotherPost.put(); // /api/undefined/1 404 (Not found)
    });
  
  }]);
  </code></pre>