Author: Paul Holden
MDL-77067 reportbuilder: indicate when audiences are used in schedules.
Indicate in each audience card whether it's used as part of a report
schedule, and inform user again upon deletion of said audience.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b9a5a3626e8a8e0d6faeb4094423e4bcb887f2e2
http://github.com/moodle/moodle/commit/b9a5a3626e8a8e0d6faeb4094423e4bcb887f2e2
+ 4.3 en [audienceusedbyschedule,core_reportbuilder]