Reply to iCalendar invitations with three commands: :accept,
:accept-tentative or :decline. Parse a text/calendar request, create a
reply and append it to the composer.
Suggested-by: Ondřej Synáček <ondrej@synacek.org>
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>
62982a9a67