openssl-1.0.1g: ChaCha20-Poly1305 build-in support

```
$ openssl ciphers -v
ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=ECDSA Enc=ChaCha20-Poly1305 Mac=AEAD
ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=RSA Enc=ChaCha20-Poly1305 Mac=AEAD
DHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=DH Au=RSA Enc=ChaCha20-Poly1305 Mac=AEAD
```

On an E5-2690 at 2.90GHz with Hyperthreading and Turboboost disabled:
- AES-128-GCM, AES-NI disabled: 131 MB/s
- AES-128-GCM, AES-NI enabled: 311 MB/s
- AES-128-GCM, AES-NI enabled & -march=native: 308 MB/s
- ChaCha20+Poly1305: 420 MB/s
- ChaCha20+Poly1305, -march=native: 560 MB/s

On a Galaxy Nexus (ARM Cortex-A9 at 1.2GHz), gcc 4.7:
- AES-128-GCM: 27 MB/s
- ChaCha20+Poly1305: 78 MB/s

http://www.ietf.org/mail-archive/web/tls/current/msg09847.html