DateUtil.java: New Method

Added new method for use with timex tag library.

public static boolean isInCurrentPayPeriod(Date checkDate) {     Date weekStartDate = getDateWithZeroTime(getCurrentPeriodStartingDate());     Date weekEndDate = getDateWithMaxTime(getCurrentPeriodEndingDate());     return (!checkDate.before(weekStartDate) && !checkDate             .after(weekEndDate)); }