title: using a ZoomContributionViewItem in a view
body: <p>I saw that it's possible to add a combo in the toolbar of a view to zoom a graph but the problem is that it's used with JFace and I just want to know if it's possible to work with this class of zest ( ZoomContributionViewItem ) only with SWT since I'm using a Graph and not a GraphViewer .</p>
  
  <p>I'm a beginner with Zest and I don't really understand the difference between the two methods ( JFace and SWT with Zest ) so would you please first tell me if it's possible to make the zoom with a graph and not a graphviewer and second explain me the difference between these methods</p>
  
  <p>Thank you so much for your help</p>