title: Error bars are not plotted when axes are reversed (plotCI from package plotrix)
body: <p>I want to change the point of origin for a plot with vertical and horizontal error bars. I'm using the plotCI function from the 'plotrix' package for plotting.</p>
  
  <p>A very short reproducible example:</p>
  
  <pre><code>x &lt;- c(1, 2)
  y &lt;- c(3, 4)
  err.x &lt;- c(0.5, 0.2)
  err.y &lt;- c(0.25, 0.3)
  plotCI(x, y, uiw = err.x, err = "x",
         ylim = range(y+err.y, y-err.y))
  plotCI(x, y, uiw = err.y, err = "y", add = T)
  </code></pre>
  
  <p>Everything is fine in this plot. I got both horizontal and vertical error bars.</p>
  
  <pre><code>plotCI(x, y, uiw = err.x, err = "x",
         ylim = rev(range(y+err.y, y-err.y)))
  plotCI(x, y, uiw = err.y, err = "y", add = T)
  </code></pre>
  
  <p>Here, I only get the horizontal error bars. It seems as if the reversal of the y-axis wasn't 'recognized' by the second call to plotCI.</p>
  
  <p>Any ideas?!? Thanks a lot!</p>