title: Delete all files in a directory
body: <p>I need to delete all files in a directory using Qt.</p>
  
  <p>All of the files in the directory will have the extension ".txt".</p>
  
  <p>I don't want to delete the directory itself.</p>
  
  <p>Does anyone know how I can do this? I've looked at QDir but am having no luck.</p>