title: Script tags being rendered after purification in WYSIWYG
body: <p>I'm having an issue with using the HTMLPurifier php library. I'm using a  WYSIWYG editor named 'Summernote' for all text areas on my application. </p>
  
  <p>When writing something inside sommernote like:</p>
  
  <p><code>&lt;script&gt;alert('test');&lt;/script&gt;</code></p>
  
  <p>The post data comes through as</p>
  
  <p><code>&lt;p&gt;&amp;lt;script&amp;gt;alert('test');&amp;lt;/script&amp;gt;&lt;/p&gt;</code></p>
  
  <p>However, once this is ran through the HTMLPurifier, it doesn't remove the script tags that are converted into regular characters. So when I go to edit this text inside summernote, it actually runs the script!</p>
  
  <p>Here's an image of what is processed into the editor:</p>
  
  <p><img src="https://i.stack.imgur.com/Svzn0.png" alt="HTML Purifier Issue"></p>
  
  <p>And here is how it's stored inside the database:</p>
  
  <p><img src="https://i.stack.imgur.com/LsXJg.png" alt="HTML Purifier Issue - 2"></p>
  
  <p>If anyone has any ideas please let me know!</p>
  
  <p>EDIT: Also, if I disable the Summernote WYSIWYG editor, the tags are successfully removed from the textarea when cleaning with HTMLPurifier.</p>