If an application calls the macro SSL_CTX_get_extra_chain_certs
return either the old "shared" extra certificates or those associated
with the current certificate.

This means applications which call SSL_CTX_use_certificate_chain_file
and retrieve the additional chain using SSL_CTX_get_extra_chain_certs
will still work. An application which only wants to check the shared
extra certificates can call the new macro
SSL_CTX_get_extra_chain_certs_only

(Imported from upstream's e0d4272a58 and
3bff195dca)

This change implements equal-preference groups of cipher suites. This
allows, for example, a server to prefer one of AES-GCM or ChaCha20
ciphers, but to allow the client to pick which one. When coupled with
clients that will boost AES-GCM in their preferences when AES-NI is
present, this allows us to use AES-GCM when the hardware exists and
ChaCha20 otherwise.

Implement ChannelID as both a client and server.

(Called "cut through" for historical reasons in this patch.)

Enables SSL3+ clients to send application data immediately following the
Finished message even when negotiating full-handshakes.  With this
patch, clients can negotiate SSL connections in 1-RTT even when
performing full-handshakes.

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)