Add contribution type and fiscal year filters to BUNT reports

Here are patches to add contribution type filter to the LYBUNT and SYBUNT reports (again, I don't see how these reports could have been useful to anyone when they are full of non-donations).
It also adds the ability to specify fiscal year as well as calendar year.
Patch to form.php adds the function fiscalYearOffset() which is now used by both reports in a number of FY sql calculations.