title: Invalid result from ngResource request with string array
body: <p>i've the following ngResource defined:</p>
  
  <pre><code>angular.module('LicenseServices', ['ngResource']).
      factory('License', function ($resource) {
          return $resource('api/licenses/:id', { id: '@id' }, {
              //...
              'getLicenseTypes': { method: 'GET', url: 'api/licenses/types', isArray: true }
          });
      });
  </code></pre>
  
  <p>The result of the GET request is:</p>
  
  <pre><code>["Trial","Standard"]
  </code></pre>
  
  <p>But using the resource in a controller:</p>
  
  <pre><code>$scope.licenseTypes = License.getLicenseTypes()
  </code></pre>
  
  <p>i get the following result:</p>
  
  <pre><code>licenseTypes: 
  [ undefined, { 
  0: S
  1: t
  2: a
  3: n
  4: d
  5: a
  6: r
  7: d
   } ]
  </code></pre>
  
  <p>I'm using AngularJS 1.1.4 with Chrome.</p>
  
  <p>Whats wrong with my resource definition?</p>