message: Link to image for violin plot
  Improves consistency with other plots on top of being generally useful.
diff: <h2>{{group_id}}</h2>
  {{#if violin_plot}}
  <h3>Violin Plot</h3>
  + <a href="violin.svg">
  <img src="violin.svg" alt="Violin Plot"/>
  + </a>
  <p>This chart shows the relationship between function/parameter and iteration time. The thickness of the shaded region indicates the probability that a measurement of the given function/parameter would take a particular amound of time.</p>
  {{/if}}
  {{#if line_chart}}
  