title: Valid method does not clear error message if it returns true
body: <p>I submit empty form, and one field is invalid. Than I change something in my form (not for current, invalid field) and invoke validation for my invalid field in code:</p>
  
  <pre><code>$('.myinvalidfield').valid()
  </code></pre>
  
  <p>It returns me that this field is valid, but doesn't remove validation error message for it. What should I do to fix it? (I dont want to remove messages and error classes by hand. It is possible to do using settings or JQuery?)</p>
  
  <p><em>Update.</em></p>
  
  <p>I have two fields, first element is not required, second is required only when first is empty. I use this rules:</p>
  
  <p>First, required field:</p>
  
  <pre><code>    required: function (element) {
          var secondElement = $(selector);
          var value = secondElement.val();
          return value == ""; //if second (not required) field has value, that current element is not required
      },
  </code></pre>
  
  <p>Second, not required field:</p>
  
  <pre><code>    required: function (element) {
          var secondElement = $(selector);
          if (secondElement.length == 0) return false; //becouse my forms builds dynamicly
          secondElement.valid(); //invoke validation for required field
          return false;
      }
  </code></pre>
  
  <p>This rules works, but if I submit the form with empty fields it show me one error for reqired field, and when I change first, not required field, then all form is valid, but the error message is not disappear from second element.</p>