Finished the server-side modifications (read more)

* There seems to be something iffy with this branch
* The size of SerialPacket may have changed

I've implemented the accountIndex variable as best I can, but I really
shouldn't code at night. I'll need to go over the changes again before
merging this.

client/scenes/lobby_menu.cpp

@@ -230,7 +230,7 @@ void LobbyMenu::HandlePacket(SerialPacket packet) {
 
 		//handle errors
 		default:
-			throw(std::runtime_error("Unknown SerialPacket::Type encountered"));
+			throw(std::runtime_error(std::string() + "Unknown SerialPacket::Type encountered in LobbyMenu: " + to_string_custom(int(packet.meta.type))));
 		break;
 	}
 }