New functions SSL[_CTX]_set_msg_callback().

New functions SSL[_CTX]_set_msg_callback().
New macros SSL[_CTX]_set_msg_callback_arg().

Message callback imlementation for SSL 3.0/TLS 1.0 (no SSL 2.0 yet).

New '-msg' option for 'openssl s_client' and 'openssl s_server'
that enable a message callback that displays all protocol messages.

In ssl3_get_client_hello (ssl/s3_srvr.c), generate a fatal alert if
client_version is smaller than the protocol version in use.
Also change ssl23_get_client_hello (ssl/s23_srvr.c) to select TLS 1.0
if the client demanded SSL 3.0 but only TLS 1.0 is enabled; then the
client will at least see that alert.

Fix SSL[_CTX]_ctrl prototype (void * instead of char * for generic
pointer).

Add/update some OpenSSL copyright notices.