Multiple security issues fixed.
- fix CVE-2016-2105 - possible overflow in base64 encoding
- fix CVE-2016-2106 - possible overflow in EVP_EncryptUpdate()
- fix CVE-2016-2107 - padding oracle in stitched AES-NI CBC-MAC
- fix CVE-2016-2108 - memory corruption in ASN.1 encoder
- fix CVE-2016-2109 - possible DoS when reading ASN.1 data from BIO