add a second kind of schedule check to next show, allowing for a fortnight-like
check against odd or even weeks of the year rather than X week per month like
the original purpose of this script. 'schedule' value is where the desired
behaviour is defined.

also added section in the second type of weekcheck to allow you to define an
end time for the event you're searching for. probably needs added as an option
to the first type of weekcheck routine and to fortnight