EXDATE different formats not handled

[DutchDynamics]

Hi

Found a problem with different formats of EXDATA in ics files.

Some calendars return it like this:
EXDATE;TZID=South Africa Standard Time:20170403T060000,20170410T060000,20170417T060000,20170501T060000

others return it like:
EXDATE;TZID=South Africa Standard Time:20170403T060000
EXDATE;TZID=South Africa Standard Time:20170410T060000
EXDATE;TZID=South Africa Standard Time:20170417T060000
EXDATE;TZID=South Africa Standard Time:20170501T060000

The last method is working fine, but the first method, is causing a toISOstring error.

[dan entous]

found this format in the spec, https://tools.ietf.org/html/rfc5545#page-120, looks like both examples are valid.

[Berzan]

'DTSTART;TZID="(UTC+01:00) Amsterdam, Berlin, Bern, Rom, Stockholm, Wien":20160821T180000'

This one doesn't work though and has yet to be fixed.