title: Make Nvd3 Pie Chart show percentages with decimals
body: <p>I'm using Nvd3 in an Angular project to draw some charts. I'm using the angular directive from Krispo's (<a href="http://krispo.github.io/angular-nvd3/#/" rel="noreferrer">http://krispo.github.io/angular-nvd3/#/</a>).</p>
  
  <p>I am showing a pie chart whose labels show the values in percents, but the values shown are being rounded and displayed without decimals.
  See an example in the plunker below:
  <a href="http://plnkr.co/edit/jSf1TAkj5rO1S7p5PuJK?p=preview" rel="noreferrer">http://plnkr.co/edit/jSf1TAkj5rO1S7p5PuJK?p=preview</a></p>
  
  <p>In the example above, the percentages should be 21,9% and 78% for example.</p>
  
  <p>I can only change the slice value format and not the label, that, in this case, is the percentage.</p>
  
  <p>This is a big issue when I have a slice that is right near 100%, because it should show something like 99,99% instead of showing 100% giving the impression that there is only one slice.</p>
  
  <p>Here is the chart configuration:</p>
  
  <pre><code>chart: {
          type: 'pieChart',
          height: 500,
          x: function(d){return d.key;},
          y: function(d){return d.y;},
          showLabels: true,
          transitionDuration: 500,
          labelThreshold: 0.01,
          legend: {
                margin: {
                   top: 5,
                   right: 35,
                   bottom: 5,
                   left: 0
                }
          },
          labelType: 'percent',
          valueFormat: function(d) {
                return d3.format(',.5f')(d);
          }
   }
  </code></pre>