Add interface selection for NetJack components

 * Multicast interface selection to UnixSocket - added methods
   Bind and JoinMCastGroup with <char *if_name> argument
 * Interface handling to NetInterface class tree - new field and
   its initialization/usage in Slave branch.
 * Multicast interface selection to NetSlaves (Adapter/Driver)
   and NetMaster, where master can now listen all interfaces.
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