title: Add 3d column values in hoverinfo when using ggplot2 object in ggplotly
body: <p>my data frame:</p>
  
  <pre><code>structure(list(CNT = c("Albania", "Algeria", "Argentina (Ciudad Autónoma de Buenos)", 
  "Australia", "Austria", "B-S-J-G (China)", "Belgium", "Brazil", 
  "Bulgaria", "Canada"), Female = c(417.75, 363.07, 446.03, 490.99, 
  483.13, 528.19, 499.74, 369.55, 442.16, 511.14), Male = c(408.55, 
  356.5, 467.31, 496.76, 510.1, 534.01, 514, 385.04, 440.32, 520.17
  )), .Names = c("CNT", "Female", "Male"), row.names = c(NA, 10L
  ), class = "data.frame")
  </code></pre>
  
  <p>I want to plot the data using a ggplot2 object and not plot_ly so that on hovering the values of all three variables are shown.</p>
  
  <p>If I do the way I want only Male and Female appears on hovering:</p>
  
  <pre><code>p&lt;-ggplot(df, aes(Female, Male)) +
    geom_point() 
  ggplotly(p)
  </code></pre>
  
  <p>I want the country name to appear as well. Looking on the web I figure it out how to do in plot_ly:</p>
  
  <pre><code>plot_ly( df, x=df$Female , y=df$Male, text=df$CNT,
  hoverinfo="text+x+y")
  </code></pre>
  
  <p>I want to achieve the same result but using a ggplot2 object as in the example above when using object p.  </p>