By Poppy McPherson and Jiraporn Kuhakan UTHAI SAWAN, Thailand (Reuters) -Grief-stricken relatives sobbed and clutched toys at a children’s daycare centre on Friday, a day after a former policeman killed 34 people, most of them young children, in a knife and gun rampage there that has horrified Thailand. Government buildings flew flags at half mast to mourn victims – 23 of them children – of the carnage in Uthai Sawan, a town 500 km (310 miles) northeast of Bangkok, the capital of the largely Buddhist country. After leaving the daycare centre filled with dead, dying and wounded, the ex-officer …