Add IPv6 support to UnixSocket and NetInterfaces

 * Cleaned up direct references to sockaddr_in
 * Changed fRecvAddr & fSendAddr to sockaddr_storage
 * Added field fFamily indicating current probed AF.
 * Added protected method ProbeAF accepting IP to probe
   and addr to fill in. As well as final call to test
   which should be either connect or bind.
 * Reworked protocol specific methods to act on fFamily
 * IsLocal now checks assigned interface addresses
 * Introduced internal state tracker to avoid double bind
 * Workaround for GLIBC bug returning wrong order of AFs
   http://sourceware.org/bugzilla/show_bug.cgi?id=14967
 * Corrected interface selection for Slaves - only one
   interface could be used to multicast the packet
 * Retab changes