Make binary curve ASN.1 work in FIPS mode.

Don't check for binary curves by checking methods: the values will
be different in FIPS mode as they are redirected to the validated module
version.
DTLS 1.2 cached record support.

Add DTLS1.2 support for cached records when computing handshake macs
instead of the MD5+SHA1 case for DTLS < 1.2 (this is a port of the
equivalent TLS 1.2 code to DTLS).
Update fixed DH requirements.

The relaxed signing requirements for fixed DH certificates apply to DTLS 1.2
too.
Enable TLS 1.2 ciphers in DTLS 1.2.

Port TLS 1.2 GCM code to DTLS. Enable use of TLS 1.2 only ciphers when in
DTLS 1.2 mode too.