title: Gnuplot xticlabels with several lines
body: <p>if I add a xticlabel that uses 3 lines gnuplot cuts at the middle of the second line.
  Is there any method to have xticlabels with several lines?</p>
  
  <p>This is my data file:</p>
  
  <pre><code>"[17h30,19h00] 25" 1
  "[03h30,10h00] 21" 1
  "[03h00,12h00] 26" 2
  "[18h00,19h30] 27" 3
  "[20h30,22h00] 25" 4
  "[13h00,14h30] 25" 4
  "[19h30,21h30] 25" 5
  "[14h30,16h00] 25" 5
  "[16h30,18h00] 25" 5
  "[09h30,15h00] 25" 9
  </code></pre>
  
  <p>And this is my gnuplot code:</p>
  
  <pre><code>set terminal postscript eps color
  set output '| epstopdf --filter --outfile=hist.pdf'
  set auto x
  set yrange [0:10]
  set style histogram clustered
  set boxwidth 0.95 relative
  set style fill transparent solid 0.5 noborder
  plot 'hist.dat' using 2:xticlabels(1) with boxes lc rgb'blue90' notitle
  </code></pre>
  
  <p>Finally this is the graph produced:</p>
  
  <p><img src="https://i.stack.imgur.com/nXYp3.png" alt="enter image description here"></p>