code: public static String getDayAsString(int day, String format) {
          SimpleDateFormat simpleFormat = new SimpleDateFormat(format);
          return simpleFormat.format(getDayAsDate(day));
      }
docs: Gets a date with a desired format as a String
  
  @param day    Can be: <li>QuickUtils.date.YESTERDAY</li><li>
  QuickUtils.date.TODAY</li><li>QuickUtils.date.TOMORROW</li>
  @param format desired format (e.g. "yyyy-MM-dd HH:mm:ss")
  @return returns a day with the given format