Author: Ruslan Kabalin
MDL-50887 antivirus: Add antivirus plugin infrastructure.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=146eeb765160ac668aec129593ee5e3a4f91477d
http://github.com/moodle/moodle/commit/146eeb765160ac668aec129593ee5e3a4f91477d
+ 3.1 en [actantivirushdr,antivirus]
+ 3.1 en [antiviruses,antivirus]
+ 3.1 en [antivirussettings,antivirus]
+ 3.1 en [configantivirusplugins,antivirus]