Reencode certificates in X509_sign_ctx as well as X509_sign.

This was causing a problem in the x509 application when it modified an
existing certificate.

Submitted by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Contributor claims ~50% improvement in CTR and ~9% in CBC decrypt
on Cortex-A15.

While ARMv7 in general is capable of unaligned access, not all instructions
actually are. And trouble is that compiler doesn't seem to differentiate
those capable and incapable of unaligned access. Side effect is that kernel
goes into endless loop retrying same instruction triggering unaligned trap.
Problem was observed in xts128.c and ccm128.c modules. It's possible to
resolve it by using (volatile u32*) casts, but letting STRICT_ALIGNMENT
be feels more appropriate.

Check for Suite B support using method flags instead of version numbers:
anything supporting TLS 1.2 cipher suites will also support Suite B.

Return an error if an attempt to use DTLS 1.0 is made in Suite B mode.

If we successfully match a cookie don't set return value to 2 as this
results in other error conditions returning 2 as well.

Instead set return value to -2 which can be checked later if everything
else is OK.

Add new methods DTLS_*_method() which support both DTLS 1.0 and DTLS 1.2 and
pick the highest version the peer supports during negotiation.

As with SSL/TLS options can change this behaviour specifically
SSL_OP_NO_DTLSv1 and SSL_OP_NO_DTLSv1_2.

Don't use Win32 specific options in mk1mf.pl to build assembly language
files.

turn out to be made somewhere by existing Makefiles.

Only use -MMD and .sinclude in copy builds: other platforms don't
support them.

Since s->method does not reflect the final client version when a client
hello is sent for SSLv23_client_method it can't be relied on to indicate
if TLS 1.2 ciphers should be used. So use the client version instead.

Give CBC decrypt approximately same treatment as to CTR and collect 25%.