CAMP BOUGAINVILLE, Kuwait, March 14 (Reuters) - United States forces fearing attack by Iraqi chemical weapons are deploying the first of a new breed of "magic trucks" to help medics treat casualties from any poisoned war zone. An inflatable tent unfurls from the back of an adapted all-terrain vehicle, swelling into a chamber designed to shield doctors from chemical weapons like nerve agents or mustard gas. "In a chemical environment, it makes medical work possible," said Captain Eric McDonald, patting the desert-coloured vehicle after a demonstration in northern Kuwait. "It gives us a clean place -- clean from dust...