title: Center Plot title in ggplot2
body: <p>This simple code (and all my scripts from this morning) has started giving me an off center title in ggplot2:</p>
  <pre><code>Ubuntu version: 16.04
  
  R studio version: Version 0.99.896
  
  R version: 3.3.2
  
  GGPLOT2 version: 2.2.0
  </code></pre>
  <p>I have freshly installed the above this morning to try and fix this...</p>
  <pre><code>dat &lt;- data.frame(
  time = factor(c(&quot;Lunch&quot;,&quot;Dinner&quot;), levels=c(&quot;Lunch&quot;,&quot;Dinner&quot;)),
  total_bill = c(14.89, 17.23)
  )
  
  # Add title, narrower bars, fill color, and change axis labels
  ggplot(data=dat, aes(x=time, y=total_bill, fill=time)) + 
    geom_bar(colour=&quot;black&quot;, fill=&quot;#DD8888&quot;, width=.8, stat=&quot;identity&quot;) + 
    guides(fill=FALSE) +
    xlab(&quot;Time of day&quot;) + ylab(&quot;Total bill&quot;) +
    ggtitle(&quot;Average bill for 2 people&quot;)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/v3zNm.png" rel="noreferrer"><img src="https://i.stack.imgur.com/v3zNm.png" alt="enter image description here" /></a></p>