title: Strange spacing of dates on x-axis (D3)
body: <p>I am trying to create a simple column chart using an array of data points of the form<code>[datetime,value]</code>, for example <code>[1422345600000,146]</code>. I would like to plot these with the date on the x-axis with labeled ticks every few days. I almost managed to accomplish this, but the first couple of ticks are spaced oddly close together. </p>
  
  <p>You can see it here: <a href="http://jsfiddle.net/9r4fqbnm/2/" rel="nofollow">http://jsfiddle.net/9r4fqbnm/2/</a></p>
  
  <p>I tried </p>
  
  <pre><code>var xAxis = d3.svg.axis()
      .scale(x)
      .orient('bottom')
      .ticks(d3.time.days,7)
      .tickFormat(d3.time.format("%m/%d/%Y"))
  </code></pre>
  
  <p>and the ticks after the first two are indeed spaced by 7 days.</p>
  
  <p>I didn't find this issue online--am I missing something obvious?</p>
  
  <p>Thanks</p>