Move socketengine stats into a new class
Change all socketengine methods to be static
Queue changes in socketengine_kqueue and submit them as we poll for new events
Call DelFd() and SetFd(-1) from SocketEngine::Close(EventHandler*)
Store the EventHandler* in the kevent/epoll_event/portev struct

This removes the need to call GetRef() for every socket in DispatchEvents()
Replace DummyExtItem with a flag in Extensible
m_sqlauth Allow the client certificate fingerprint to be used in the SQL query

Idea by @m4z
m_operjoin Remove duplicated code
Wait for the manager bind to come back before sending search in LDAP modules
Remove redundant null pointer check from m_ldapauth
Remove support for advertising the SSL ports in RPL_ISUPPORT.

- No other IRC servers implement this.
- No IRC clients I can find support this.