title: Google Spreadsheets columns export to CSV
body: <p>I would like to create csv file from Google spreadsheet automatically (after clicking button).
  But I don't want to export whole spreadsheet but just few columns.
  How can I do this?</p>
  
  <p>eg. spreadsheets has 8 columns and I would like to export first three to csv with values like: "column1 value; column2 value; column3 value; column1 value; column2 value; ... "</p>
  
  <p>Thank you</p>