Author: David Balch
MDL-58919 assignsubmission_file: Add accepted file types default.
New setting "defaultacceptedfiletypes" to define default accepted file
types in File submissions.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=797a70c0ecfd58c7e3f323eb688103f9e6e3941e
http://github.com/moodle/moodle/commit/797a70c0ecfd58c7e3f323eb688103f9e6e3941e
+ 3.4 en [defaultacceptedfiletypes,assignsubmission_file]