Update Csocket to 1d7e685

> Extend EDisableProtocol
> missing ifdef for non-ssl
> added ability to disable compression
> added new callbacks for Certificate Verification and Handshake completion
> added SNI support for client and server, cleanup some of the certificate verification callback code
Fix non-SSL build
Fix #719: Disable SSL compression
Config option for SSL protocols (resolves #720)

ZNC currently disables SSLv2 and SSLv3 by default. To keep the ZNC
defaults (recommended, may change in the future versions) and for
example disable TLSv1 in addition, specify in the global config
section:

    SSLProtocols = -TLSv1

Available (case-insentive) values are:

    All, SSLv2, SSLv3, TLSv1, TLSv1.1, TLSv1.2

A non-prefixed "absolute" value overrides the ZNC defaults:

    SSLProtocols = TLSV1 +TLSv1.1 +TLSv1.2
Merge pull request #728 from jpnurmi/ssl-protocols

Config option for SSL protocols (#720)