Author: Peter
MDL-33671 core: Allow for bulk delete of files
* Enable bulk delete in a details view
* Behat tests for new functionality
* Unit test for new function
http://git.moodle.org/gw?p=moodle.git;a=commit;h=2f039236023b9f770aa22de4b01eb88e4069c3cd
http://github.com/moodle/moodle/commit/2f039236023b9f770aa22de4b01eb88e4069c3cd
+ 3.9 en [confirmdeleteselectedfile,core_repository]
+ 3.9 en [deleteselected,core_repository]
+ 3.9 en [nofilesselected,core_repository]