Change test so it passes on JDK 8
Rename EPOCH_MONTH to PROLEPTIC_MONTH
Rename periodUntil() to until()
Rename and promote isDateBased()/isTimeBased()
Rename toString() to format()
Rename and promote isDateBased()/isTimeBased()
Make era classes public
Add UnsupportedTemporalTypeException
Add isSupported(TemporalUnit)
Remove field/unit name
Add Period.ofWeeks()
Add ZoneId.getAvailableZoneIds()
Refactor to ZoneId.SHORT_IDS