Support import of time zones (RFC 5545)

The property parameter time zone identifier (TZID) is recognized in DTSTART,
DTEND and EXDATE and the DATE-TIME value converted to a local time. The time
zone identifier is logged in the note file.

Signed-off-by: Lars Henriksen <LarsHenriksen@get2net.dk>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

test/data/ical-007.ical

@@ -10,4 +10,9 @@ SUMMARY:UTC
 DTSTART:20150223T110000Z
 DURATION:PT1H
 END:VEVENT
+BEGIN:VEVENT
+SUMMARY:CET
+DTSTART;TZID=CET:20150223T110000
+DURATION:PT1H
+END:VEVENT
 END:VCALENDAR

test/data/ical-008.ical

@@ -1,8 +1,8 @@
 BEGIN:VCALENDAR
 VERSION:2.0
 BEGIN:VEVENT
-DTSTART;TZID="(UTC+01:00) Amsterdam, Berlin, Bern, Rom, Stockholm, Wien":19800101T000100
-DURATION:P1DT9H17M0S
+DTSTART:19800101T000100
+DURATION;TESTPARAM="Quoted string with colon(:), semicolon(;) and comma(,)":P1DT9H17M0S
 SUMMARY:Calibrator's
 END:VEVENT
 BEGIN:VTODO