As a last resort, match packets to processes when only the local part matches

Helps for applications with many short-lived connections (such as bittorrent)
and is correct except for exotic use cases anyway

packet.h

@@ -74,6 +74,7 @@ public:
 	bool Outgoing ();
 
 	bool match (Packet * other);
+	bool matchSource (Packet * other);
 	/* returns '1.2.3.4:5-1.2.3.4:6'-style string */
 	char * gethashstring();
 private: