(cherry picked from commit 1f44dac24d1cb752b1a06be9091bb03a88a8598e)

Whitespace fixes

If multiple TLS extensions are expected but not received, the TLS extension and supplemental data 'generate' callbacks are the only chance for the receive-side to trigger a specific TLS alert during the handshake.

Removed logic which no-op'd TLS extension generate callbacks (as the generate callbacks need to always be called in order to trigger alerts), and updated the serverinfo-specific custom TLS extension callbacks to track which custom TLS extensions were received by the client, where no-ops for 'generate' callbacks are appropriate.

PR#3106

Conflicts:
	apps/s_server.c

Free generated supp data after handshake completion, add comment regarding use of num_renegotiations in TLS and supp data generation callbacks

Add callbacks supporting generation and retrieval of supplemental data entries, facilitating RFC 5878 (TLS auth extensions)
Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.

This change adds support for ALPN[1] in OpenSSL. ALPN is the IETF
blessed version of NPN and we'll be supporting both ALPN and NPN for
some time yet.

[1] https://tools.ietf.org/html/draft-ietf-tls-applayerprotoneg-00

Conflicts:
	ssl/ssl3.h
	ssl/t1_lib.c

Contributed by Trevor Perrin.

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.

Add correct flags for DTLS 1.2, update s_server and s_client to handle
DTLS 1.2 methods.

Currently no support for version negotiation: i.e. if client/server selects
DTLS 1.2 it is that or nothing.

Just a sample, real world applications would have to be cleverer.

Add new verify options to set checks.

Remove previous -check* commands from s_client and s_server.

Add support for separate verify and chain stores in s_client.

to the SSL_CONF APIs.

This is complicated a little because the SSL_CTX structure is not available
when the command line is processed: so just check syntax of commands initially
and store them, ready to apply later.

certificate. Add options to s_client, s_server and x509 utilities
to print results of checks.

by client and send back to server. Also prints an abbreviated summary of
the connection parameters.