'next' and 'prev' links incorrect in month view.

In 1.378 the value of $duration was changed in the month view (to the number of days in the month I think). But later that value is passed to _event_nav, which increases the date by 30 months or so.

The problem seems to be that _event_nav's $duration parameter is documented as: "The duration of the current view in multiples of view type" (months in this case), while event_calendar_ical it is: "The number of days the feeds duration is". So $duration means different things in different places.

There's a similar problem in the week view.

This was only introduced yesterday, so sorry for jumping on it so quickly.