Don't include znc.h in Listener.h

znc.h pulls in most headers, Socket.h pulls in way less headers. This should
speed up compiles by 0.0000000314%.

The rest of this is compile fixes for stuff which assumed that Listener.h
includes znc.h for them. :-)

Signed-off-by: Uli Schlachter <psychon@znc.in>

modules/certauth.cpp

@@ -11,6 +11,7 @@
 #include "Modules.h"
 #include "User.h"
 #include "Listener.h"
+#include "znc.h"
 
 class CSSLClientCertMod : public CGlobalModule {
 public: