title: How to ignore empty attributes within a composite component?
body: <p>How can i ignore empty attributes of a composite component?
  Example:</p>
  
  <pre><code>&lt;cc:interface&gt;
  &lt;cc:attribute name="styleClass" /&gt;
  &lt;cc:attribute name="value" /&gt;
  &lt;/cc:interface&gt;
  
  &lt;cc:implementation&gt;
  &lt;h:inputText styleClass="#{cc.attrs.styleClass}"
      value="#{cc.attrs.value}"&gt;
      &lt;cc:insertChildren /&gt;
  &lt;/h:inputText&gt;
  &lt;/cc:implementation&gt;
  </code></pre>
  
  <p>When i use the component by this:</p>
  
  <pre><code>&lt;my:inputText /&gt;
  </code></pre>
  
  <p>It is rendered like this:</p>
  
  <pre><code>&lt;input type="text" class="" /&gt;
  </code></pre>
  
  <p>How can i get an output without the empty class-attribute?</p>