backported patches from xulrunner fixes mfsa2012-{57,58,63,65,70}

also known as
CVE-2012-1970, CVE-2012-1972, CVE-2012-1973, CVE-2012-1974,
CVE-2012-1975, CVE-2012-1976, CVE-2012-3959, CVE-2012-3962,
CVE-2012-3969, CVE-2012-3972, CVE-2012-3978.