title: ggplot title not working?
body: <p>I'm using the ggplot2 library in R and trying to put a title on my ggplot but it's telling me the ggtitle function doesn't exist! </p>
  
  <p>This is my code: </p>
  
  <pre><code>p &lt;- ggplot (data, aes(x, y)) +
    geom_point(shape= 21, fill= "blue", colour= "black", size=2) +
    xlab("X Value") + ylab("Y Value") +
    geom_smooth(method= "lm", se= FALSE,  colour= "red", formula=y ~ poly(x, 3, raw=TRUE)) +
    geom_errorbar(aes(ymin=y-SE, ymax=y+SE), width=.9)
  p
  </code></pre>
  
  <p>I tried this but it isn't working:</p>
  
  <pre><code>    p &lt;- ggplot (data, aes(x, y)) +
        geom_point(shape= 21, fill= "blue", colour= "black", size=2) +
        xlab("X Value") + ylab("Y Value") +
        geom_smooth(method= "lm", se= FALSE,  colour= "red", formula=y ~ poly(x, 3, raw=TRUE)) +
        geom_errorbar(aes(ymin=y-SE, ymax=y+SE), width=.9) + 
        ggtitle( "title")
      p
  </code></pre>
  
  <p>Any help would be appreciated!</p>