Author: Paul Holden
MDL-77056 reportbuilder: relative date filter for before given period.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=198db552b037769d314b5b5d3e10b6da5830f85a
http://github.com/moodle/moodle/commit/198db552b037769d314b5b5d3e10b6da5830f85a
+ 4.2 en [filterdatebefore,core_reportbuilder]