EXDATE with multiple values is not folded

[zvasilev]

resources/ical/011.ics.out

line 14 , per RFC 5545, EXDATE should be folded also.
EXDATE;TZID=US/Central:20170706T090000,20170713T090000,20170720T090000,20170803T090000

Same case for
resources/ical/013.ics.out
line 147
RRULE:FREQ=WEEKLY;UNTIL=20210309T080000Z;INTERVAL=1;BYDAY=MO,TU,WE,TH,FR,SA;WKST=MO