Document Moodle security advisories from January (MSA-17-0001 - MSF-17-0004)
and March releases (details not yet released).

Security: CVE-2017-2576
Security: CVE-2017-2578
Security: CVE-2016-10045
Security: https://vuxml.FreeBSD.org/freebsd/f72d98d1-0b7e-11e7-970f-002590263bf5.html
Security: https://vuxml.FreeBSD.org/freebsd/df45b4bd-0b7f-11e7-970f-002590263bf5.html