Document multiple security issues of PHP 7.0

Security: CVE-2016-7416
Security: CVE-2016-7412
Security: CVE-2016-7414
Security: CVE-2016-7417
Security: CVE-2016-7413
Security: CVE-2016-7418
Security: https://vuxml.freebsd.org/freebsd/f471032a-8700-11e6-8d93-00248c0c745d.html

Approved by: pi (mentor)