Let EventServer and other services using XBMC's Socket.h listen on IPv6 ...

...addresses.
Cosmetics: use PF_INET6 rather than AF_INET6 as arg for socket()

In a full dual-stack environment where both  AAAA and A DNS records exist for an xbmc host, remote clients (e.g. the official remote for android) will be unable to connec to to the xbmc host's event server, because the client choses IPv6 over IPv4, and the event server only listens on IPV4.
This PR lets the Event server (and, I guess, other services) receive both IPv4 and IPv6 packets.
Tested on 64bit Linux and Android.
It may fail on an OS without any IPv6 support. Are there still any of those around in the list of supported OSs?