old_contents: var incrementDate = function incrementDate(date_str, incrementor) {
      var parts = date_str.split("-");
      var dt = new Date(
          parseInt(parts[0], 10),      // year
          parseInt(parts[1], 10) - 1,  // month (starts with 0)
          parseInt(parts[2], 10)       // date
      );
      dt.setTime(dt.getTime() + incrementor * 86400000);
      parts[0] = "" + dt.getFullYear();
      parts[1] = "" + (dt.getMonth() + 1);
      if (parts[1].length < 2) {
          parts[1] = "0" + parts[1];
      }
      parts[2] = "" + dt.getDate();
      if (parts[2].length < 2) {
          parts[2] = "0" + parts[2];
      }
      return parts.join("-");
  }
  
new_contents: // http://stackoverflow.com/a/29199863/4021614
  var incrementDate = function incrementDate(date_str, incrementor) {
      var parts = date_str.split("-");
      var dt = new Date(
          parseInt(parts[0], 10),      // year
          parseInt(parts[1], 10) - 1,  // month (starts with 0)
          parseInt(parts[2], 10)       // date
      );
      dt.setTime(dt.getTime() + incrementor * 86400000);
      parts[0] = "" + dt.getFullYear();
      parts[1] = "" + (dt.getMonth() + 1);
      if (parts[1].length < 2) {
          parts[1] = "0" + parts[1];
      }
      parts[2] = "" + dt.getDate();
      if (parts[2].length < 2) {
          parts[2] = "0" + parts[2];
      }
      return parts.join("-");
  };
  
subject: add semicolon and S.O. link