Need filter type for single date on report

We have been getting report requests with a single date criteria - ie. please give us all people who contributed before this date & not after or the slightly more complex PTP requirements where the cut-off date combines with other criteria to generate a set of periods to compare.

At the moment the only date field filter operator types available assume a range whereas we need a single date op criteria.

I have attached the patch that seems to work on this for us. Note that the value of the constant (3) is probably wrong - but anything with a 4 in it triggered the date range behaviour in criteria.tpl