Fix end time of recurring events

The UNTIL date in RRULE specs were being ignored as the code had event_until = max(event_until, end_utc); I think you mean "min" here so that event_until is the smallest of those two dates.
last day of daily repeat was being omitted.

Here is a sample event generated by google calendar for an event that occurs over 3 days.  In the master, the script was generating only 2 days org entries; with the simple change here, you also get the last day.


```
BEGIN:VEVENT
DTSTART;TZID=Europe/London:20131216T170000
DTEND;TZID=Europe/London:20131216T180000
RRULE:FREQ=DAILY;UNTIL=20131218T170000Z
DTSTAMP:20131214T184616Z
CREATED:20131214T184507Z
DESCRIPTION:
LAST-MODIFIED:20131214T184608Z
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Three day event
TRANSP:OPAQUE
END:VEVENT
```
Merge pull request #4 from sje30/patch-2

last day of daily repeat was being omitted (patch from Stephen Eglen)
Merge pull request #2 from sje30/patch-1

Fix end time of recurring events. Patch from Stephen Eglen.
Complete rewriting of ical2org using iterators.
fix little bug.
fix bug.
Do not use EventRecurDailyIter/EventRecurWeeklyIter. Use EventRecurDaysIter instead.