If a component was given with full ical (including the BEGIN:VCALENDAR-tag) but (a) leading blank(s), and some other field also was given, then the BEGIN/END:VCALENDAR tags got duplicated
is-defined and is-not-defined search for class did not work
New icalendar generation code: don't autogenerate a uuid if we already have an uuid
Some exception got thrown in the get_duration-logic.