title: Customise the infoWindow / tooltip in R --> plotly
body: <p>I am new to plot.ly and I just drew my first scatter plot out of R the other day - its great! </p>
  
  <pre><code>testplot &lt;- ggplot(a, aes(OR_Edu, OR_Illn, color=Country, size=total)) + geom_point()
  py$ggplotly(testplot)
  </code></pre>
  
  <p><a href="https://plot.ly/~SyTpp/14/or-illn-vs-or-edu/" rel="nofollow">https://plot.ly/~SyTpp/14/or-illn-vs-or-edu/</a></p>
  
  <p>Now, I would like to change the tooltip or the little info window that pops up on hover over a datapoint. In this case I am not interested in the y-coordinate but instead I would like to display the country name and the population size, which I mapped to the aestectic size. </p>
  
  <p>Ideally I would like to know if/how I can customize the infowindow in general, maybe even display variables in my dataframe for each country which I don't give the plot in aes(), e.g. the GDP of a country etc etc..</p>
  
  <p>Thanks!</p>