1.5.0

Add format() function to DateTime to convert a DateTime to a string with a specified format.
Add valueOf() method to DateTime and Duration
Add dayOfYear() and utcDayOfYear() to DateTime returning the n-th day of the year, starting at 0
Add weekNumber() utility function (ISO week number)
Add weekNumber() and utcWeekNumber() methods to DateTime
Add weekOfMonth() utility function (ISO week number)
Add weekOfMonth() and utcWeekOfMonth() methods to DateTime
Add secondOfDay() utility function (ISO week number)
Add secondOfDay() and utcSecondOfDay() methods to DateTime
Add abbreviationForUtc() to TimeZone
Add zoneAbbreviation() to DateTime to get time zone abbreviation at the specified datetime.