[Dhooks] Add the ability to work with the this parameter, which is an object

[A1mDev]

Sometimes we have to work with this parameter which is a class but dhooks doesn't have this feature, this PR solves this problem. This code has been tested on both post and pre hooks. Below is an example code for working with the new functionality.

/*class CBaseEntity : public IServerEntity
{
	...
protected:
	EHANDLE m_pParent;  // for movement hierarchy	
	...
};*/

MRESReturn Handler_CBaseEntity__OnTakeDamage(Address pThis, Handle hReturn, Handle hParams)
{
	// If EHANDLE type or entity returns entity index.
	// Index num 0, for working with this parameter

	int iParent = DHookGetParamObjectPtrVar(hParams, 0, 384, ObjectValueType_Ehandle);
	if (iParent < 1 || !IsValidEntity(iParent)) {
		return MRES_Ignored;
	}

	char sEntityName[64];
	GetEntityClassname(iParent, sEntityName, sizeof(sEntityName));
	
	PrintToChatAll("[Handler_CBaseEntity__OnTakeDamage] iParent: %s (%d)", sEntityName, iParent);
	
	return MRES_Ignored;
}