title: how to write a blank column with CSVPrinter of apache.commons.csv
body: <p>I am using CSVPrinter in order to read and write CSV. While writing CSV,
  I want to write a blank column such like that "x",,"y" (the second column). But unfortunately it writes as "x","","y". How I can write a blank column by using CSVPrinter? I used following stuff in order to write it . Even, I could not find it in the CSVPrinter documentation. Please help me.</p>
  
  <p>printer.print(null)  -> ""
  printer.print("") -> ""</p>
  
  <p>Thanks</p>