Extend use of note file for iCal import

iCal import to an item note file is extended from DESCRIPTION to
LOCATION, COMMENT and STATUS for both events and todos.

Addresses GitHub issue #9.

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

test/data/ical-009.ical

@@ -63,6 +63,19 @@ BEGIN:VTODO
 PRIORITY:1
 SUMMARY:an unescaped comma: ,
 END:VTODO
+BEGIN:VEVENT
+DTSTART:20200406T221300
+DURATION:PT0H15M0S
+SUMMARY:Invalid STATUS
+STATUS:confirmed
+END:VEVENT
+BEGIN:VEVENT
+DTSTART:20200406T221300
+DURATION:PT0H15M0S
+SUMMARY:LOCATION twice
+LOCATION:first
+LOCATION:second
+END:VEVENT
 BEGIN:VTODO
 SUMMARY:finally\, missing end of item
 END:VCALENDAR