title: Can i add icon to primeng button?
body: <p>i have been trying to add icon from <a href="http://seehowsupport.com/font-awesome/" rel="noreferrer">http://seehowsupport.com/font-awesome/</a> website to my p-button. </p>
  
  <pre><code>&lt;div class="ui-g-12"&gt;
      &lt;button pButton id="selectFile" (click)="selectFile()" label="+ Select File..."&gt;&lt;/button&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>here, in place of '+' in label, i wish to set icon from above url. I have heard changing some content attribute in css to \f067 can do it but m not sure how to.
  Thanks</p>