Author: Brendan Heywood
MDL-69513 email: Add support for email DKIM signatures
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1b47d4bc0e7eb9dd2d24e232008cc2771b7b11a1
http://github.com/moodle/moodle/commit/1b47d4bc0e7eb9dd2d24e232008cc2771b7b11a1
+ 4.0 en [configemaildkimselector,core_admin]
+ 4.0 en [emaildkim,core_admin]
+ 4.0 en [emaildkimselector,core_admin]
+ 4.0 en [emaildkiminfo,core_admin]