title: Matlab: Delete box on annotation textbox, or creating a multiple line annotation text without box
body: <p>I am writing the equation of a plane in an annotation of my 3D plot. I do not need a box, but since the only option that I have found has a box, is it possible to delete it?</p>
  
  <pre><code>str = {'z=a+bx+cy','a=0.2','b=1.2','c=0.3'};
  annH = annotation('textbox',[0.8 0.9 0.08 0.08],'string',str)
  </code></pre>
  
  <p>I tried to get the list of the property of annH with set(annH) but I do not see anything as 'box','off' or similar.
  Thanks
  A.</p>