0aa50bbf

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

ical: parse and retain the X-WR-TIMEZONE calendar property

X-WR-TIMEZONE is a non-standard property (not in RFC 5545) that virtually every
real-world calendar producer emits (Google Calendar, Apple, ...) to declare the
calendar's default display time zone. The parser previously dropped it, leaving
consumers unable to render floating/UTC times in the calendar's intended zone.

Add it as an optional Calendar property (calendarTimeZoneIdentifier), mirroring
METHOD: new CalendarTimeZoneIdentifier property type + IsProperty, a Maybe field
on Calendar, GenValid, and a PropertySpec (roundtrip + X-WR-TIMEZONE:Europe/Warsaw
example). Bumps ical to 0.2.0.0 (adds a Calendar field).

Timeline