Add callbacks supporting generation and retrieval of supplemental data...

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.

(cherry picked from commit 36086186)
Conflicts:
	Configure
	apps/s_client.c
	apps/s_server.c
	ssl/ssl.h
	ssl/ssl3.h
	ssl/ssltest.c