By Poppy McPherson and Jiraporn Kuhakan UTHAI SAWAN, Thailand (Reuters) -Hundreds gathered in temples in northeast Thailand on Saturday, offering candles, toys and prayers to mark the lives of more than 30 mostly child victims of a gun and knife rampage that shocked the world. Most of the children, aged 2 to 5, were slashed to death on Thursday, while adults were shot, police said in the aftermath of one of the world’s worst recent child death tolls in a massacre by a single killer. At the Si Uthai temple in the village of Uthai Sawan, relatives and family of the dead joined a devastated commu…