Config option for disabled SSL protocols (#720)

In the global config section:
SSLDisabledProtocol = <value1>
SSLDisabledProtocol = <value2>
...

Available values are: None, SSLv2, SSLv3, TLSv1
`SSLDisabledProtocol = SSLv2` in config disables SSLv3 too, because `m_uDisabledSSLProtocols = Csock::EDP_SSL;`, and this line will do nothing.