title: NSTextView insert image in between text
body: <p>Is it possible to insert an image (not a background image) into an <code>NSTextView</code>? 
  Something like:</p>
  
  <pre>Hi :) How are you?</pre> 
  
  <p>and it should display a "smiley" image. I have an <code>NSTextView</code> and an <code>NSImage</code>.</p>