Cut down on some HP update spam

This increases the timer that mobs will send out updates
(It could probably be increased more)
This will also reset the timer every time SendHPUpdate is called
to prevent sending like 3+ completely useless updates at once
Also skip sending the update to the client if we're sending an
OP_Damage with the damage since the client will apply this number

zone/mob.h

@@ -508,7 +508,8 @@ public:
 	static void CreateSpawnPacket(EQApplicationPacket* app, NewSpawn_Struct* ns);
 	virtual void FillSpawnStruct(NewSpawn_Struct* ns, Mob* ForWho);
 	void CreateHPPacket(EQApplicationPacket* app);
-	void SendHPUpdate();
+	void SendHPUpdate(bool skip_self = false);
+	virtual void ResetHPUpdateTimer() {}; // does nothing
 
 	//Util
 	static uint32 RandomTimer(int min, int max);