anchor.diff:        if (!remoteFileUrl.match(urlPattern)) {
           // add warning to input field
           //console.log("bad url:", remoteFileUrl);
  -        inputField.closest('.form-group').addClass('error');
  +        inputField.closest('.form-group').addClass('has-error');
           inputField.after('<span class="help-block">Fix the URL</span>');
           return;
         }
  
positive.code:         ).success(function(data) {
            contentType = data["content-type"];
            if (!contentType.match(/audio/)) {
              inputField.closest('.form-group').addClass('error');
              inputField.after('<span class="help-block">Not a valid audio link</span>');
              return;
            } else {
  
negative.code:       // validate file extension(s). If any fail, they all fail.
  
        // clear any error first
        element.closest('.form-group').removeClass('has-error');
        element.next('.alert-danger').remove();
        var numValid = 0;
        angular.forEach(newFiles, function(file) {
          if (!$scope.looksLikeValidFileName(file.name)) {
            element.closest('.form-group').addClass('has-error');
            element.after('<div class="alert alert-danger">Not a valid audio file: '+file.name+'</div>');
          }
          else {
            numValid++;
  