- Updated the comments for open_socket_in().

- Updated the comments for open_socket_in().
- Changed open_socket_in() to return an array of ints with a trailing -1
  value to indicate the end of the list.
- Use the out_of_memory() routine to complain about no memory.
- Undid the recent IPV6_V6ONLY change, as I think it would prevent the
  use of IPv6 sockets on some older systems.
- If we get an EADDRINUSE error and this is not the first socket in the
  list, suggest that the user try --ipv4 or --ipv6.
- When forking, the child now closes all the open bound sockets, not just
  one of them (I'm not talking about the fd from accept(), obviously).