Duck: make duck custom packets go through the snapshot system

[LordSk]

Like that:

teeworlds/src/game/server/entities/laser.cpp

Lines 105 to 107 in e55aab4

	CNetObj_Laser *pObj = static_cast<CNetObj_Laser *>(Server()->SnapNewItem(NETOBJTYPE_LASER, GetID(), sizeof(CNetObj_Laser)));
	if(!pObj)
	return;