Two British terror suspects accused of being involved in the execution of Western hostages, as well as Salford aid worker Alan Henning, have denied all charges against them in a US court.El Shafee Elsheikh, 32, and Alexanda Kotey, 36, are accused of beheading hostages for the so-called Islamic State in Syria.Both are accused of being involved in the executions of four American citizens, as well as British and Japanese nationals.The two men, who grew up in London, are said to have been part of a