Split up the serial code, but had to gut it in the process

Since the contents of the packets are different than before, I decided to
gut the serialization code. I'll reimplement the internals soon.

common/network/packet/serial_packet_base.hpp

@@ -38,9 +38,10 @@ struct SerialPacketBase {
 	IPaddress srcAddress;
 
 	typedef SerialPacketType Type;
+
+	virtual ~SerialPacketBase();
 };
 
-typedef SerialPacketBase* SerialPacket;
-typedef SerialPacketType PacketType;
+typedef SerialPacketBase SerialPacket;
 
 #endif