Working on merging the v6-addr branch. This is checkpoint, tests don't

pass yet.

Changes:

- Gave IPAddress/IPPrefix methods AsString() so that one doesn't need
  to cast to get a string represenation.

- Val::AsAddr()/AsSubnet() return references rather than pointers. I
  find that more intuitive.

- ODesc/Serializer/SerializationFormat get methods to support
  IPAddress/IPPrefix directly.

- Reformatted the comments in IPAddr.h from /// to /** style.

- Given IPPrefix a Contains() method.

- A bit of cleanup.

src/DCE_RPC.h

@@ -65,7 +65,7 @@ struct dce_rpc_endpoint_addr {
 		{
 		static char buf[128];
 		snprintf(buf, sizeof(buf), "%s/%d/%s",
-			addr->AsString().c_str(), port,
+			addr.AsString().c_str(), port,
 			proto == TRANSPORT_TCP ? "tcp" :
 			(proto == TRANSPORT_UDP ? "udp" : "?"));