By Brendan O’Brien and Steve Gorman (Reuters) -A fierce tornado blasted through Little Rock, Arkansas, and adjacent towns on Friday, ripping away roofs and walls from many buildings, flipping over vehicles, and leaving at least two dozen people hospitalized. The University of Arkansas for Medical Sciences hospital, the region’s only major trauma center, declared a level-1 mass casualty alert after the tornado struck Little Rock, the state’s capital and most populous city, at mid-afternoon. No deaths were reported from the twister, spawned by one of a number of thunderstorms s...