* dbus/dbus-server.c (dbus_server_listen): change how this works
	to be able to delegate to a set of handlers that can succeed,
	fail, or choose not to handle. Allows us to have
	dbus_server_listen_platform_specific.

	* dbus/dbus-server-socket.c (_dbus_server_new_for_tcp_socket):
	factor out the tcp socket stuff to be used on windows, leaving
	unix domain socket only in dbus-socket-unix.c

	* dbus/dbus-transport-socket.c
	(_dbus_transport_new_for_tcp_socket): factor out the tcp socket
	stuff to be used on windows, leaving unix domain socket only
	in dbus-transport-unix.c

	* dbus/dbus-connection.c (dbus_connection_get_unix_user): insert
	temporary hack to be sure this fails on windows
	(dbus_connection_get_unix_process_id): ditto