title: D3 V4 setting initial zoom level
body: <p>I've just started using D3 V4 and I'm having trouble getting a pan and zoom function working. The problem is that I want the initial scale value to be something over than 1 so I set this using</p>
  
  <pre><code>zoom.scaleTo(svg, 2);
  </code></pre>
  
  <p>However as soon as I pan or zoom the scale resets back to 1.</p>
  
  <p>Here's an example of this behavior on JSFiddle, what am I doing wrong?</p>
  
  <p><a href="https://jsfiddle.net/skgktrcu/" rel="noreferrer">JSFiddle</a></p>