Reviewed-by: NTim Hudson <tjh@openssl.org>

RT#3625
Reviewed-by: NEmilia Käsper <emilia@openssl.org>

The only support for SSLv2 left is receiving a SSLv2 compatible client hello.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

(cherry picked from commit 1f44dac24d1cb752b1a06be9091bb03a88a8598e)

PR#3172

Add -ecdh_single option to set SSL_OP_SINGLE_ECDH_USE on the command line.
(cherry picked from commit f14a4a861d2d221ed565a75441a218f85b8db530)

Extend SSL_CONF to return command value types.

Add certificate and key options.

Update documentation.