thunderbird: multiple issues

• CVE-2016-1955 (same-origin policy bypass)

A vulnerability allows remote attackers to bypass the Same Origin Policy
and obtain sensitive information by reading a Content Security Policy
(CSP) violation report that contains path information associated with an
IFRAME element.

• CVE-2016-1956 (denial of service)

Security researcher Ucha Gobejishvili reported a denial of service (DOS)
attack when doing certain WebGL operations in a canvas requiring an
unusually large amount buffer to be allocated from video memory. This
resulted memory resource exhaustion with some Intel video cards,
requiring the computer to be rebooted to return functionality. This was
resolved by putting in additional checks on the amount of memory to be
allocated during graphics processing.