title: linecap property in highchart doesn't work
body: <p>Is there any example of linecap in highcharts. <a href="http://api.highcharts.com/highstock#plotOptions.line.linecap" rel="nofollow">http://api.highcharts.com/highstock#plotOptions.line.linecap</a></p>
  
  <p>I want to change it from round to butt. but it's not working.</p>