#110 Allow older SSL protocols to be disabled

[Dave Heller]

With recent attention to vulnerabilities in older SSL protocols, it is useful to have a way to disable the protocols easily. This patch adds two new configuration properties, "sslNoSSLv3" and "sslNoTLSv1" to disable the indicated protocol. This sets the corresponding openssl option SSL_OP_NO_SSLv3 or SSL_OP_NO_TLSv1 as appropriate. See man SSL_CTX_set_options(3) for details.

There is no option to enable SSLv2. I figured that was not useful and would just open the possibility of misconfiguration. The code can be easily modified of this is required.

[Dave Heller]

Commit [155e19] for v1.3
Commit [decd3c] for v1.4