title: Set R plots x axis to show at y=0
body: <p>Usually when I plot some R line plot and set <code>ylim=c(0,some_value)</code>, there is small space between the x axis and y=0.</p>
  
  <p>I would like the y axis to show exactly at y=0 so points (x,0) will be plotted on the y axis (and not above).</p>