title: plotly multiple plot facet
body: <p>I'd like to do multi plots with two axes on each plot like this</p>
  
  <pre><code>library(plotly)
  ay &lt;- list(
    tickfont = list(color = "green"),
    overlaying = "y",
    side = "right", title = "y2 axis title"
  )
  
  
  par(mfrow=c(2,1))
  ax &lt;-list(title = "x axis title")
  ay1 &lt;-list(title = "y1 axds title")
  plot_ly(x = 1:3, y = 10*(1:3), name = "slope of 10") %&gt;%
    add_trace(x = 2:4, y = 1:3, name = "slope of 1", yaxis = "y2") %&gt;%
    layout(title = "Double Y Axis", yaxis2 = ay, xaxis = ax, yaxis = ay1) 
  
  
   ax &lt;-list(title = "x axis title")
   ay1 &lt;-list(title = "y1 axds title")
   plot_ly(x = 1:3, y = 10*(1:3), name = "slope of 10") %&gt;%
     add_trace(x = 2:4, y = 1:3, name = "slope of 1", yaxis = "y2") %&gt;%
     layout(title = "Double Y Axis", yaxis2 = ay, xaxis = ax, yaxis = ay1) 
  </code></pre>
  
  <p>but when you run that code you still only see one plot. Can <code>plotly</code> do multi plots? Can it do faceting with two axes?</p>