Add security tests for vulnerabilities released 2012-10-25

This includes tests for:

  CVE-2012-4730  Email header injection
  CVE-2012-4731  Create Article without proper rights
  CVE-2012-4732  CSRF blacklist evasion
  CVE-2012-4734  Confused deputy during login
  CVE-2012-4735  Improper signing or encryption of GnuPG messages
Merge branch 'security/4.0/tests' into 4.0-trunk