title: ggplot boxplot with geom_jitter legend title
body: <p>I am trying to create a box-plot with data points via geom_jitter. I cant find a way to change to legend title for the variable "clin" used to color the data points.</p>
  
  <pre><code>p&lt;-ggplot(plot1, aes(culture, score,fill=group))
  p+geom_boxplot()+ggtitle("title")+
  ylab("y")+ xlab("x")+
  guides(fill=guide_legend(title="In-vitro response"))+
  scale_fill_grey(start = 0.6, end = 1)+
  geom_jitter(aes(colour = clin), alpha=0.4) 
  </code></pre>
  
  <p>Data:</p>
  
  <pre><code>score group culture clin
  1   a   co  y
  3   a   co  y
  7   a   co  y
  5   a   co  y
  5   a   co  y
  5   b   co  y
  6   b   co  y
  9   b   co  n
  7   b   co  n
  8   b   co  n
  6   b   co  n
  9   b   co  n
  9   a   mon y
  9   a   mon y
  6   a   mon y
  6   a   mon n
  5   a   mon y
  4   b   mon y
  4   b   mon y
  3   b   mon n
  3   a   mon n
  3   b   mon n
  3   b   mon n
  3   b   mon n
  </code></pre>
  
  <p>NEED TO CHANGE TITLE FOR SECOND LEGEND: "CLIN"</p>
  
  <p><img src="https://i.stack.imgur.com/4uGwu.jpg" alt=""></p>