title: FineUploader does not show error messages
body: <p>If have implemented fine uploader and can upload files. I have also set the allowed extensions to only allow PDF.</p>
  
  <p>But when I try to upload and jpg for instance nothing happens.</p>
  
  <p>Normally this is not a problem but i would like to see a message. This works on the fineuploader website but not for me. </p>
  
  <p>Hope someone can help me.</p>
  
  <p>code: </p>
  
  <pre><code>createUpload({ button: $('#dienstverleningsDocumentUploader'), 
  endpoint:'/adviseur/profile/dienstverleningsDocument/' + '@Model.Adviseur.ServiceDocumentID',
  messages: $('#dienstverleningsDocumentMessage'), allowedExtensions: ['pdf'] });
  
  function createUpload(options) {
  var button = options.button[0];//Should be a jQuery $(...)
  var endpoint = options.endpoint;
  var allowedExtensions = options.allowedExtensions || ['doc', 'xls', 'docx', 'xlsx', 'pdf'];
  var sizeLimit = options.sizeLimit || 10000000;// 10Mb
  var itemLimit = options.itemLimit || 10;
  var messages = options.messages || $('#messages');
  var complete = options.complete;
  
  return new qq.FineUploaderBasic({
      button: button,
      request: {
          endpoint: endpoint
      },
      validation: {
          allowedExtensions: allowedExtensions,
          sizeLimit: sizeLimit,
          itemLimit: itemLimit
      },
      callbacks: {
          onSubmit: function (id, fileName) {
              messages.html('&lt;div id="file-' + id + '" class="alert" style="margin: 20px 0 0"&gt;&lt;/div&gt;');
          },
          onUpload: function (id, fileName) {
              $('#file-' + id).addClass('alert-info')
                              .html('&lt;img src="client/loading.gif" alt="Initializing. Please hold."&gt; ' +
                                    'Initializing ' +
                                    '“' + fileName + '”');
          },
          onProgress: function (id, fileName, loaded, total) {
              if (loaded &lt; total) {
                  progress = Math.round(loaded / total * 100) + '% of ' + Math.round(total / 1024) + ' kB';
                  $('#file-' + id).removeClass('alert-info')
                                  .html('&lt;img src="client/loading.gif" alt="In progress. Please hold."&gt; ' +
                                        'Uploading ' +
                                        '“' + fileName + '” ' +
                                        progress);
              } else {
                  $('#file-' + id).addClass('alert-info')
                                  .html('&lt;img src="client/loading.gif" alt="Saving. Please hold."&gt; ' +
                                        'Saving ' +
                                        '“' + fileName + '”');
              }
          },
          onComplete: function (id, fileName, responseJSON) {
              if (responseJSON.success) {
                  $('#file-' + id).removeClass('alert-info')
                                  .addClass('alert-success')
                                  .html('&lt;i class="icon-ok"&gt;&lt;/i&gt; ' +
                                        '“' + fileName + '”' +
                                        'succesvol.'
                                        );
                  if (complete) {
                      complete(fileName, responseJSON);
                  }
              } else {
                  $('#file-' + id).removeClass('alert-info')
                                  .addClass('alert-error')
                                  .html('&lt;i class="icon-exclamation-sign"&gt;&lt;/i&gt; ' +
                                        'Uploaden mislukt bij: ' +
                                        '“' + fileName + '”: ' +
                                        responseJSON.error);
              }
          }
      }
  });
  }
  </code></pre>