Set SSL options for increased security

Disable SSLv2, SSLv3, and compression; generate new DH or ECDH keys
during each handshake; always start a new session on server
renegotiation; set a strong cipher list.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

[ Patch from https://code.google.com/p/shellinabox/issues/detail?id=215 ]
Add dynamic linking for functions required by SSL v2/3 disabling patch.