A Dutch wildlife photographer taken hostage by militants linked to Islamic State has been killed in the southern Philippines.Elwold Horn, 59, from Holland, was shot by his captors after a firefight broke out on Friday between government security forces and militants belonging to the Abu Sayyaf terrorist group on the island of Sulu.Six militants were killed, twelve wounded in the fighting when troops from the 32nd Infantry Battalion raided the militants’ hideout in the village of Pansul, Patikul…