Upgrade

1.x to 2.0

Factory methods were moved or renamed:

• Date::today() is unchanged

• Date::createJulianDay() -> Date::createFromJulianDay()

• Date::create() -> Calendar::create()

• Date::parse() -> Calendar::parse()

• Date::fromDateTime() -> Calendar::fromDateTime()

• Date::parseDateTimeString() -> Calendar::parseDateTimeString()