title: missing plot title in ggplot2
body: <p>How can I create a plot title in ggplot2? Am I making a silly syntax error?</p>
  
  <p>The <a href="http://docs.ggplot2.org/current/labs.html" rel="nofollow">ggplot2 docs</a> indicate that labs(title = 'foo') should work, but I can only get the arguments <code>x='foo'</code> and <code>y='foo'</code> to work with <code>labs()</code>. Neither <code>ggtitle()</code> nor <code>title()</code> worked either.</p>
  
  <p>Here is an example.</p>
  
  <pre><code>x &lt;- rnorm(10,10,1)
  y &lt;- rnorm(10,20,2)
  xy.df &lt;- data.frame(x,y)
  qplot(x,y, data=xy.df, geom='point', color=x*y) + 
    labs(title = "New Plot Title",
         x='Some Data', 
         y='Some Other Data')
  </code></pre>