title: Change Size of Tick Labels D3
body: <p>I want to increase the size of the numbers which label my legend using D3.  The legend is made as follows:</p>
  
  <pre><code>map.legend_axes = d3.svg.axis()
              .scale(map.legend_scales)
              .orient('bottom')
              .tickSize(map.settings.legend.ticks);
  </code></pre>
  
  <p>Is there an argument I can pass which will increase the size of the numbers?  </p>