End date of multi-all-day event is shifted by one day

[doak]

A all-day event spanning several days will be created one day too long.

For example the following event will last to Nov 5th 2016, altough it should only last to Nov 4th according to RFC 5545:

The "DTEND" property for a "VEVENT" calendar component specifies the non-inclusive end of the event.

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//PYVOBJECT//NONSGML Version 1//EN
BEGIN:VEVENT
DTSTART;VALUE=DATE:20161031
DTEND;VALUE=DATE:20161105
SUMMARY:Allerheiligen 2016 (bayern)
TRANSP:TRANSPARENT
END:VEVENT
END:VCALENDAR