title: textInput Layout destroyed by jui Datepicker in yii2 basic
body: <p>tried to use jui/Datepicker within an ActiveForm:</p>
  
  <pre><code>&lt;?= $form-&gt;field($model, 'valid_to')-&gt;textInput()-&gt;widget(DatePicker::className(),['clientOptions' =&gt; ['defaultDate' =&gt; '2014-01-01'],'dateFormat' =&gt; 'yyyy-MM-dd']) ?&gt;    
  </code></pre>
  
  <p>It works fine but unfortunaltely, it destroys the layout of the inputFiel of yii2´s "basic" template like this:
  the label is no longer located on top of the field but on the left, the surrounding of the field won´t be colored in green / red after js validation.</p>
  
  <p>Is there a property of DatePicker like "do not override input field css"? What´s the right thing to do to solve this?</p>
  
  <p>Following doesn´t work:</p>
  
  <p>Here is the yii2 code:</p>
  
  <pre><code>&lt;?= $form-&gt;field($model, 'id_currency')-&gt;textInput() ?&gt;
  &lt;?= $form-&gt;field($model, 'valid_to')-&gt;widget(DatePicker::className(),['class' =&gt; 'form-control','clientOptions' =&gt; ['defaultDate' =&gt; '2014-01-01'],'dateFormat' =&gt; 'yyyy-MM-dd']) ?&gt;
  </code></pre>
  
  <p>Output HTML:</p>
  
  <pre><code>&lt;div class="form-group field-license-id_currency required"&gt;
  &lt;label class="control-label" for="license-id_currency"&gt;Id Currency&lt;/label&gt;
  &lt;input type="text" id="license-id_currency" class="form-control" name="license[id_currency]"&gt;
  
  &lt;div class="form-group field-license-valid_to required"&gt;
  &lt;label class="control-label" for="license-valid_to"&gt;Valid To&lt;/label&gt;
  &lt;input type="text" id="license-valid_to" name="license[valid_to]"&gt;
  </code></pre>
  
  <p>class="form-control" is missing in the datePicker input Field.</p>