lib: fixed parsing of recurring VEVENTS: DAILY and interval support
The library routines that parsed vevent data did not handle DAILY
recurrence at all. This is added.
Also, the WEEKLY, MONTHLY, and YEARLY recurrence parsing did not
take into account the interval (i.e. every other day, or every 3
weeks, etc). This is also added.
Where assumptions need to be made, warnings are now printed in
verbose mode, via barryverbose().
Safety code, such as making sure Interval is correctly set at the
start of the parsing, is also added.