title: Change comma and thousand separator in tick labels
body: <p>In a chart like the one below I wan to change the thousand separator to a dot ".", but I don't know how to use the <code>tickformat</code> parameter in order to get it. </p>
  
  <pre><code>require(plotly)
  p &lt;- plot_ly(x=~c(2012,2013,2014,2015,2016), y=~c(1200000,975000,1420000,1175000,1360000), type='bar') %&gt;%
       layout(yaxis = list(title="Income in €", tickformat=",d", gridcolor = "#bbb"), xaxis = list(title="Year"), margin=list(l=80))
  p
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/6x0o5.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/6x0o5.jpg" alt="enter image description here"></a></p>