title: add line break in axis labels of 3d plot – plotly
body: <p>Inserting <code>&lt;br&gt;</code> in the axis labels – as suggested <a href="https://stackoverflow.com/questions/35185143/how-to-create-new-line-in-plot-ly-js-title/35212889#comment87192641_35212889">in this other post</a> – does not work in <em>3d plot</em></p>
  
  <p>any suggestions? </p>
  
  <p>Thanks</p>
  
  <p>ps: this is how the code looks like, for a 3d plot </p>
  
  <pre><code>layout = go.Layout(
  title='my_title',
  scene=dict(
      xaxis=dict(
          title='x_title' + '&lt;br&gt;' + 'at new line',
          titlefont=dict(
              size=18
          )
      ),
      yaxis=dict(
          title='y_title' + '&lt;br&gt;' + 'at new line',
          titlefont=dict(
              size=18
          )
      ),
      zaxis=dict(
          title='z_title' + '&lt;br&gt;' + 'at new line',
          titlefont=dict(
              size=18
          )
      )
  )
  </code></pre>